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WO2023018592A1 - Dispositif électroluminescent à semi-conducteur avec réflecteur multicouche en champ proche - Google Patents

Dispositif électroluminescent à semi-conducteur avec réflecteur multicouche en champ proche Download PDF

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Publication number
WO2023018592A1
WO2023018592A1 PCT/US2022/039377 US2022039377W WO2023018592A1 WO 2023018592 A1 WO2023018592 A1 WO 2023018592A1 US 2022039377 W US2022039377 W US 2022039377W WO 2023018592 A1 WO2023018592 A1 WO 2023018592A1
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Prior art keywords
layer
mlr
semiconductor layer
doped
undoped
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PCT/US2022/039377
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English (en)
Inventor
Aleksandr VASKIN
Mohamed S. ABDELKHALIK
Debapriya PAL
Jaime Gomez Rivas
Albert Femius Koenderink
Toni Lopez
Aimi Abass
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Lumileds Llc
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Publication date
Priority claimed from US17/879,948 external-priority patent/US20230051992A1/en
Application filed by Lumileds Llc filed Critical Lumileds Llc
Priority to KR1020247008477A priority Critical patent/KR20240037381A/ko
Priority to EP22761762.8A priority patent/EP4385074A1/fr
Priority to CN202280069243.3A priority patent/CN118103998A/zh
Publication of WO2023018592A1 publication Critical patent/WO2023018592A1/fr

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/84—Coatings, e.g. passivation layers or antireflective coatings
    • H10H20/841—Reflective coatings, e.g. dielectric Bragg reflectors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/83—Electrodes
    • H10H20/831—Electrodes characterised by their shape
    • H10H20/8316—Multi-layer electrodes comprising at least one discontinuous layer
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/862—Resonant cavity structures
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/882—Scattering means

Definitions

  • the field of the present invention relates to semiconductor light-emitting devices.
  • a semiconductor light-emitting device is disclosed that includes a near-field multi-layer reflector.
  • An inventive semiconductor light-emitting device comprises a semiconductor diode structure and a multi-layer reflector (MLR) structure.
  • the semiconductor diode structure includes first and second doped semiconductor layers and an active layer between a back surface of the first semiconductor layer and a front surface of the second semiconductor layer.
  • the active layer emits output light, resulting from electrical current flow through the device, at a nominal emission vacuum wavelength Xo to propagate within the diode structure.
  • the MLR structure is positioned against a back surface of the second semiconductor layer, and includes layers of dielectric materials of two or more different refractive indices.
  • the MLR structure reflects output light incident thereon from within the second semiconductor layer.
  • the second semiconductor layer is sufficiently thin so that the MLR structure is in near-field proximity to the active layer relative to the vacuum wavelength o. At least a portion of a front surface of the first semiconductor layer is arranged as a device exit surface through which at least a portion of the output light, propagating perpendicularly within the diode structure relative to the device exit surface and incident on the device exit surface within the diode structure, exits the diode structure as device output light.
  • An inventive light-emitting device can further include a metal layer on a back surface of the MLR structure so that the MLR structure is between the metal layer and the back surface of the semiconductor layer.
  • An inventive light-emitting device can further include a plurality of optical scattering elements arranged within one or more layers of the MLR structure. The scattering elements can scatter laterally-propagating output light to propagate perpendicularly relative to the device exit surface; such scattering can be induced by, e.g., diffraction from scattering elements arranged periodically or quasi-periodically within the MLR structure.
  • the device exit surface of an inventive light-emitting device can include an anti-reflection layer or coating.
  • Nearfield proximity of the MLR structure to the active layer, and structural arrangement of the MLR structure can result in the device exhibiting one or more of: (i) a relatively enhanced Purcell factor, (ii) a relatively increased fraction of output light propagating within a device escape cone, (iii) a relatively reduced mean total number of internal redirections and internal reflections per photon of output light before exiting the device, or (iv) a relatively enhanced photon extraction efficiency.
  • FIGs. 1 -4 are schematic cross-sectional views of three general examples of an inventive light-emitting device.
  • Fig. 5A is a schematic cross-sectional view of a specific example of an inventive light-emitting device
  • Fig. 5B is a table listing the layer arrangement of the device of Fig. 5A
  • Fig. 5C is a sine-corrected plot of radiant intensity versus emission angle for the device of Fig. 5A and two conventional reference devices
  • Fig. 5D is a table of performance parameters of the device of Fig. 5A and the two conventional reference devices.
  • Fig. 6A is a schematic cross-sectional view of another specific example of an inventive light-emitting device
  • Fig. 6B is a table listing the layer arrangement of the device of Fig. 6A
  • Fig. 6C is a sine-corrected plot of radiant intensity versus emission angle for the device of Fig. 6A and two conventional reference devices
  • Fig. 6D is a table of performance parameters of the device of Fig. 6A and the two conventional reference devices.
  • Fig. 7A is a schematic cross-sectional view of another specific example of an inventive light-emitting device
  • Fig. 7B is a table listing the layer arrangement of the device of Fig. 7A
  • Fig. 7C is a sine-corrected plot of radiant intensity versus emission angle for the device of Fig. 7A and two conventional reference devices
  • Fig. 7D is a table of performance parameters of the device of Fig. 7A and the two conventional reference devices.
  • Fig. 8A is a schematic cross-sectional view of a specific example of an inventive light-emitting device
  • Fig. 8B is a table listing the layer arrangement of the device of Fig. 8A
  • Fig. 8C is a sine-corrected plot of radiant intensity versus emission angle for the device of Fig. 8A and two conventional reference devices
  • Fig. 8D is a table of performance parameters of the device of Fig. 8A and the two conventional reference devices.
  • Fig. 9A is a schematic cross-sectional view of a specific example of an inventive light-emitting device
  • Fig. 9B is a table listing the layer arrangement of the device of Fig. 9A
  • Fig. 9C is a sine-corrected plot of radiant intensity versus emission angle for the device of Fig. 9A and two conventional reference devices
  • Fig. 9D is a table of performance parameters of the device of Fig. 9A and the two conventional reference devices.
  • Figs. 10 and 11 are schematic cross-sectional views of two conventional lightemitting devices.
  • Figs. 12A and 12B are plots of radiant intensity (sine-corrected in Fig. 12B) as a function of emission angle for the devices of Figs. 10 and 11 .
  • Typical light-emitting diodes include one or more light-emitting active layers within a semiconductor diode structure that emit light when driven by an electric current.
  • the back surface of the semiconductor diode structure typically includes a reflector that reflects light incident within the semiconductor diode structure to propagate toward the front surface of the diode structure (also referred to herein as the exit surface or escape surface).
  • Many semiconductor materials have relatively large refractive indices (often around 3 or more) which would result in a large fraction of the emitted light being trapped within the semiconductor diode structure by total internal reflection.
  • texturing e.g., corrugations, bumps or dimples, or other surface features or roughness
  • the back-surface reflector in such so-called cavity emitters ensures that nearly all light propagating within the semiconductor diode structure eventually is incident on the front surface.
  • the front-surface texturing serves to spoil total internal reflection at least partly, allowing a portion of the emitted light to escape the semiconductor diode structure through the front surface as device output light, while redirecting other portions propagate to within the semiconductor diode structure in directions that differ from that of a specular reflection from a flat exit surface.
  • a conventional LED cavity emitter 10 is illustrated schematically in Fig. 10 and includes a semiconductor diode structure 12, a lightemitting active layer 14 within the semiconductor diode structure 12, texturing 16 on the front surface of the semiconductor diode structure 12, and a metal reflector 18 on the back surface of the semiconductor diode structure 12.
  • Another example of a conventional LED cavity emitter 20 is illustrated schematically in Fig. 11 and includes a semiconductor diode structure 12, a light-emitting active layer 14 within the semiconductor diode structure 12, texturing 16 on the front surface of the diode structure 12, a dielectric layer 19 on the back surface of the diode structure 12, and a metal reflector 18 on the back surface of the dielectric layer 19.
  • Figs. 10 includes a semiconductor diode structure 12, a lightemitting active layer 14 within the semiconductor diode structure 12, texturing 16 on the front surface of the diode structure 12, a dielectric layer 19 on the back surface of the diode structure 12, and a metal reflector 18 on the back surface of the di
  • Figs. 12A and 12B are plots of radiant intensity as a function of emission angle relative to the direction normal to the active layer 14 (sine-corrected in Fig. 12B, to account for integration over the full range of azimuthal angles).
  • the probability per bounce of a photon being transmitted through the front surface is relatively low, which in turn requires a relatively large number of round trips to achieve a sufficiently high probability of photon extraction (e.g., 10 to 50 bounces to achieve extraction efficiency approaching 90%, depending on the particular materials employed).
  • That relatively high number of round trips or photon bounces in turn requires sufficiently low optical loss per round trip through the semiconductor diode structure (e.g., loss due to absorption by the diode structure, active layer, or reflector materials, or insufficient reflectivity of the reflector).
  • That low- loss requirement in some cases can drive up the cost or complexity of the lightemitting device (e.g.: use of a silver reflector instead of aluminum; use of a multi-layer thin film reflector instead of a metal reflector; or use of higher-purity materials for diode structure, active layer, or reflector), or result in devices with low extraction efficiency (e.g., if low-loss alternatives are unavailable or cost-prohibitive).
  • Devices arranged according to Fig. 10 can be “tuned” by selecting a suitable distance between the active layer 14 and the metal layer 18 that results in increased total radiated emission and a higher fraction of emitted light propagating within an escape cone (relative to a so-called semi-infinite half-cavity model, in which no structures are near enough to the active layer 14 to affect its emission characteristics).
  • Devices arranged according to Fig. 10 also tend to have lower extraction efficiency due to unwanted absorption by the metal layer 18. That absorption can be reduced, and extraction efficiency increased, by arranging devices according to Fig. 11 to include the dielectric layer 19. However, devices arranged according to Fig. 11 tend to exhibit decrease total radiative emission and a smaller fraction of emitted light propagating within the escape cone.
  • incidentence angle and “angle of incidence” of light incident on a surface or interface refers to the angle between the propagation direction of the incident light and a vector normal to the surface or interface. Accordingly, light propagating at normal incidence with respect to a surface would have an incidence angle of 0°, while light propagating near grazing incidence with respect to that surface would have an incidence angle approaching 90°.
  • critical angle (designated by 0c) for light incident on a surface or interface between media of differing refractive indices refers to the incidence angle, for light propagating within the higher index medium, above which the light undergoes total internal reflection within the higher-index medium.
  • the critical angle 0c therefore defines an escape cone with respect to a given surface or interface, so that light incident outside the escape cone is totally internally reflected and light incident within the escape cone can be transmitted by refraction.
  • oblique light For purposes of the present disclosure and appended claims, “oblique light”, “oblique radiation”, “obliquely propagating”, “lateral light”, “lateral radiation”, “laterally propagating”, and so forth shall refer to light propagating within a substrate, layer, or diode structure at incidence angles greater than 0c with respect to the front and back surfaces thereof (i.e.
  • perpendicular light shall refer to light propagating within a substrate or diode structure at incidence angles less than 0c with respect to those surfaces (i.e., inside the escape cone), even if not literally perpendicular to the surface or vertical; “normal” shall be reserved to describe light incident at an incidence angle substantially equal to 0°.
  • any arrangement of a layer, surface, substrate, diode structure, or other structure “on,” “over,” or “against” another such structure shall encompass arrangements with direct contact between the two structures as well as arrangements including some intervening structure between them.
  • any arrangement of a layer, surface, substrate, diode structure, or other structure “directly on,” “directly over,” or “directly against” another such structure shall encompass only arrangements with direct contact between the two structures.
  • a layer, structure, or material described as “transparent” and “substantially transparent” shall exhibit, at the nominal emission vacuum wavelength Xo, a level of optical transmission that is sufficiently high, or a level of optical loss (due to absorption, scattering, or other loss mechanism) that is sufficiently low, that the lightemitting device can function within operationally acceptable parameters (e.g., output power or luminance, conversion or extraction efficiency, or other figures-of-merit including those described below).
  • an inventive light-emitting device 300 that exhibits one or more of (at least relative to one or both of the arrangements of Figs. 10 or 11 ): (i) enhanced photon extraction efficiency (e.g., 80% or more), (ii) reduced number of photon bounces (e.g., 30 or fewer), (iii) enhanced total radiated emission, (iv) enhanced Purcell factor, or (v) enhanced fraction of emitted light propagating within an escape cone before first encountering an escape surface.
  • an inventive semiconductor light-emitting device 300 that can achieve one or more of those improvements includes a semiconductor diode structure 310 and a multi-layer reflector (MLR) structure 320.
  • MLR multi-layer reflector
  • the semiconductor diode structure 310 includes first and second doped semiconductor layers 311 and 312, respectively, and an active layer 314 between them.
  • the first semiconductor layer 311 is an n-type semiconductor
  • the second semiconductor layer 312 is a p-type semiconductor.
  • the active layer 314 is arranged for emitting output light at a nominal emission vacuum wavelength Xo, resulting from electrical current flow through the device 300. The emitted output light propagates within the diode structure 310.
  • the diode structure 310 typically is arranged as a semiconductor light-emitting diode (LED).
  • the diode structure 310 typically can include one or more doped or undoped lll-V, ll-VI, or Group IV semiconductor materials or alloys or mixtures thereof. Common materials employed include Ill-nitride materials (for emission in, e.g., the near-UV and blue portions of the optical spectrum) and lll-phosphide materials (for emission in, e.g., the yellow, red, and near-IR portions of the optical spectrum); other one or more suitable materials can be employed.
  • the active layer 314 can be arranged in any suitable way for emitting light in response to electrical current flowing through the diode structure 310.
  • the active layer can include, e.g., one or more p-n junctions, one or more quantum wells, one or more multi-quantum wells, or one or more quantum dots.
  • the nominal emission vacuum wavelength Xo can be greater than about 0.20 pm, greater than about 0.40 pm, greater than about 0.8 pm, less than about 10. pm, less than about 2.5 pm, or less than about 1 .0 pm.
  • the multi-layer reflector (MLR) structure 320 is positioned against a back surface of the second semiconductor layer 312 and includes two or more layers of dielectric materials of two or more different refractive indices.
  • the collective arrangement of the dielectric layers of the MLR structure 320 reflects output light incident thereon from within the second semiconductor layer 312.
  • a common arrangement for the MLR structure is as a distributed Bragg reflector (DBR); other suitable multi-layer reflector arrangements can be employed.
  • DBR distributed Bragg reflector
  • the second semiconductor layer 312 is sufficiently thin so that the MLR structure 320 is in nearfield proximity to the active layer 314 relative to the vacuum wavelength Xo.
  • the distance between the active layer 314 and the MLR structure 320 can be less than about Xo/n, less than about Xo/2n, less than about Xo/4n, or less than about Xo/1On, where n is the effective refractive index of the second semiconductor layer 312.
  • At least a portion of a front surface of the first semiconductor layer 311 is arranged as a device exit surface 317 in contact with an external medium 99 (e.g., ambient air or a sapphire substrate).
  • an external medium 99 e.g., ambient air or a sapphire substrate.
  • the entire front surface of the first semiconductor layer 311 can be arranged as the device exit surface 317. In other examples only a first portion of the front surface of the first semiconductor layer 311 is arranged as the device output surface 317.
  • a second portion of the front surface of the first semiconductor layer 311 can be arranged so as to exhibit specular or non-specular internal reflective redirection of output light incident on the front surface from within the diode structure 300; photons redirected by those portions can make another round trip through the diode structure 310.
  • the light-emitting device 300 can further include a metal layer 305 on a back surface of the MLR structure 320 (i.e. , so that the MLR structure 320 is between the metal layer 305 and the back surface of the semiconductor layer 312).
  • the metal layer 305 can include one or more of aluminum, silver, or gold.
  • Some examples that include a metal layer 305 can also include a substantially transparent dielectric layer 306 between the metal layer 305 and the MLR structure 320 (e.g., as in Figs. 2 and 3).
  • Such a dielectric layer 306 can include one or more materials among: doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers. Some examples that include a dielectric layer 306 can also include an additional MLR structure 321 between the metal layer 305 and the dielectric layer 306 (e.g., as in Fig. 3).
  • the metal layer 305 can enhance the overall reflectivity of the MLR structure 320.
  • the metal layer 305 can serve as an electrical contact to the light-emitting device 300.
  • the device 300 can further include one or more electrically conductive vias 308.
  • Each via 308 can be arranged as a localized, circumscribed electrical conduction path through the MLR structure 320 (and the dielectric layer 306 or the additional MLR structure 321 , if present) between the metal layer 305 and the second semiconductor layer 312.
  • the vias 308 can connect directly to the second semiconductor layer 312 (e.g., as in Figs. 1-3).
  • the device 300 can include a substantially transparent electrode layer 309 between the MLR structure 320 and the back surface of the second semiconductor layer 312 (e.g., as in Fig. 4); the vias 308 provide an electrical conduction path between the metal layer 305 and the semiconductor layer 312 by being connected to the electrode layer 309, which is in direct contact with the semiconductor layer 312.
  • the transparent electrode layer 309 can include one or more of indium tin oxide (ITO), indium zinc oxide, or one or more other transparent conductive oxides.
  • ITO indium tin oxide
  • an electrode layer 309 can also include one or both of a dielectric layer 306 or an additional MLR structure 321.
  • any suitable dielectric materials can be employed for forming the MLR structure 320 (and additional MLR structure 321 if present), including one or more materials among: doped or undoped silicon; one or more doped or undoped lll-V, ll-VI, or Group IV semiconductors; doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers.
  • the MLR structure 320 (or the additional MLR structure 321 if present) can include layers of titanium oxide or niobium oxide interleaved with layers of silica.
  • Design or optimization of the diode structure 310 and MLR structure 320 can be performed (by calculation, simulation, or iterative designing/making/testing of prototypes or test devices) based on one or more selected figures-of-merit (FOMs).
  • FOMs that are often considered can include, e.g.: (i) Purcell factor (Pf; relative spontaneous emission rate affected by environment; Pf defines the total emitted power normalized to the emission in homogeneous medium); (ii) total radiated emission (tot. rad. em.
  • Inventive devices 300 arranged according to Figs. 1 -4 can be optimized to exhibit improvement with respect to one or more of the FOMs mentioned above. It is believed that near-field proximity of the MLR structure 320 to the active layer 314 can enhance the spontaneous emission rate, and can alter the spatial distribution of that emission to be directed more perpendicularly than emission without the MLR structure 320 present. Together those effects can result in a larger fraction of emitted light propagating within a specified escape cone.
  • the dielectric layers of the MLR structure 320 are also believed to reduce absorption losses per round trip relative to, e.g., the arrangement of Fig. 10.
  • the multiple layer thicknesses in the MLR structure 320 also provide a larger number of parameters that can be tuned in a given optimization process, providing opportunities for improvements relative to the conventional devices of Figs. 10 and 11.
  • FIG. 5A A layer structure for one specific example of an inventive device 300 is illustrated schematically in Fig. 5A, which includes alternating layers 320a/b/c/d of silica and niobium oxide and is optimized for a nominal emission vacuum wavelength of 450 nm; layer thicknesses and compositions are shown in the table of Fig. 5B. Plots of sine-corrected, angle-dependent radiant intensity are shown in Fig. 5C for the device of Fig. 5A compared to devices arranged according to Figs. 10 and 11 .
  • the device of Fig. 5A exhibits an enhanced fraction of light emitted within the escape cone for a GaN device against an external medium 99 of air, relative to the devices of Figs. 10 and 11 (ca.
  • FIG. 6A A layer structure for one specific example of an inventive device 300 is illustrated schematically in Fig. 6A, which includes the MLR structure 320 (alternating layers 320a/b/c/d/e/f/g of silica and niobium oxide), a silica dielectric layer 306, and an additional MLR structure 321 (alternating layers of silica and niobium oxide and a layer of aluminum oxide).
  • the structure of Fig. 6A is optimized for a nominal emission vacuum wavelength of 441 nm; layer thicknesses and compositions are shown in the table of Fig. 6B.
  • Plots of sine-corrected, angle-dependent radiant intensity are shown in Fig. 6C for the device of Fig. 6A compared to devices arranged according to Figs.
  • the device of Fig. 6A exhibits an enhanced fraction of light emitted within the escape cone for a GaN device against an external medium 99 of air, relative to the devices of Figs. 10 and 11 (ca. 36% and 54% improvement, respectively).
  • Light emitted within the escape cone has the best chance of leaving the device 300 upon first incidence on the escape surface 317, and directing a larger fraction of emitted light to propagate within the escape cone can increase the overall efficiency of the inventive light-emitting device 300.
  • any of the devices of Figs. 1 -4 can further include a plurality of optical scattering elements arranged within one or more layers of the MLR structure 320. Those scattering elements can be arranged to scatter at least a portion of output light, that propagates laterally within the diode structure 310 relative to the device exit surface 317, to propagate perpendicularly relative to the device exit surface 317.
  • An effect of the scattering elements is to increase the likelihood that light emitted to propagate laterally (i.e., outside the escape cone) would be scattered during a round trip through the diode structure 300 to propagate perpendicularly (i.e., within the escape cone) on a subsequent round trip, thereby increasing the probability of transmission through the exit surface 317 in a smaller median number of round trips.
  • the presence of the scattering elements provide additional device parameters that can be manipulated to optimize the device 300 (fully or partly) with respect to one or more selected FOMs.
  • the scattering elements can include one or more volumes of dielectric material within one or more corresponding layers of the MLR structure 320; the dielectric material of each one of those scattering elements would differ from material of the corresponding layer of the MLR structure with respect to refractive index.
  • the MLR structure 320 can include layers of titanium oxide or niobium oxide interleaved with layers of silica, and the scattering elements can include one or both of (i) titanium oxide or niobium oxide elements within one or more of the silica layers, or (ii) silica scattering elements within one or more of the titanium oxide or niobium oxide layers.
  • the scattering elements can include one or more volumes of metallic material (e.g., aluminum, silver, or gold) within one or more corresponding layers of the MLR structure 320.
  • the scattering elements can include one or more nano-antennae or one or more meta-atoms or meta-molecules within one or more layers of the MLR structure 320 (e.g., as disclosed in (i) U.S. non-provisional App. No.
  • size of or spacing between scattering elements can be less than about o/n, less than about z.o/2/?, less than about z.o/4/?, or less than about o/1On, n being the effective index of the second semiconductor layer 312.
  • the scattering elements can include one or more materials among: one or more metals or metal alloys; doped or undoped silicon; one or more doped or undoped lll-V, ll-VI, or Group IV semiconductors; doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers.
  • the scattering elements can be arranged within one or more corresponding layers of the MLR structure 320 as a corresponding periodic array within the corresponding layer of the MLR structure 320; such an array can be of any suitable type or arrangement, e.g., a rectangular, hexagonal, or trigonal array.
  • the scattering elements can be arranged within one or more corresponding layers of the MLR structure 320 in an irregular or aperiodic arrangement. Any of those arrangements, or other suitable arrangements of scattering elements arranged within one or more layers of an MLR structure 320, can be employed, optimized (fully or partly) for any one or more suitable FOMs.
  • the layers 320a-320j include layers of silica and titanium oxide. Scattering elements are arranged in the mixed titanium oxide and silica layers 320b and 320f as 60 nm substantially square titanium oxide elements arranged on a 100 nm grid within a silica layer. A dielectric layer 306 of silica separated the silver metal layer 305 from the MLR structure 320.
  • the device of Fig. 7A is optimized for a nominal emission vacuum wavelength of 440 nm; layer thicknesses and compositions are shown in the table of Fig. 7B. Plots of sine-corrected, angledependent radiant intensity are shown in Fig. 7C for the device of Fig.
  • the device of Fig. 7A compared to devices arranged according to Figs. 10 and 11.
  • the device of Fig. 7A exhibits an enhanced fraction of light emitted within the escape cone for a GaN device against an external medium 99 of air, relative to the devices of Figs. 10 and 11 (ca. 50% and 43% improvement, respectively), enhanced total radiated emission relative to the devices of Figs. 10 and 11 (ca. 1 % and 3.6% improvement, respectively), and enhanced radiation efficiency relative to the device of Fig. 10 (ca. 2% improvement).
  • the MLR structure 320 includes a titanium oxide layer 320a and a mixed titanium oxide and silica layer 320b.
  • the scattering elements are arranged in the mixed titanium oxide and silica layer 320b as 162 nm substantially cylindrical silica elements arranged on a 210 nm grid within a titanium oxide layer.
  • the device of Fig. 8A is optimized for a nominal emission vacuum wavelength of 450 nm; layer thicknesses and compositions are shown in the table of Fig. 8B.
  • Plots of sine- corrected, angle-dependent radiant intensity are shown in Fig. 8C for the device of Fig. 8A compared to devices arranged according to Figs. 10 and 11 .
  • the device of Fig. 8A exhibits an enhanced fraction of light emitted within the escape cone for a GaN device against an external medium 99 of air, relative to the devices of Figs. 10 and 11 (ca. 36% and 55% improvement, respectively).
  • the MLR structure 320 includes a mixed titanium oxide and silica layer 320a and a titanium oxide layer 320b.
  • the scattering elements are arranged in the mixed titanium oxide and silica layer 320a as 140 nm substantially cylindrical silica elements arranged on a 200 nm grid within a titanium oxide layer.
  • the device of Fig. 9A is optimized for a nominal emission vacuum wavelength of 450 nm; layer thicknesses and compositions are shown in the table of Fig. 9B.
  • Plots of sine- corrected, angle-dependent radiant intensity are shown in Fig. 9C for the device of Fig. 9A compared to devices arranged according to Figs. 10 and 11 .
  • near-field proximity of the MLR structure 320 to the active layer 314, and structural arrangement of the MLR structure 320 can result in the device 300 exhibiting a Purcell factor that is greater than about 1 .01 , greater than about 1 .02, greater than about 1 .03, greater than about 1 .04, greater than about 1.05, or even higher.
  • near-field proximity of the MLR structure 320 to the active layer 314, and structural arrangement of the MLR structure 320 (and one or both of a dielectric layer 306 or an additional MLR structure 321 , if present), can result in a fraction of output light propagating within the diode structure 310 toward the front surface of the first semiconductor layer 311 , within an escape cone defined by an interface between the first semiconductor layer 311 and an external medium 99 (e.g., ambient air), that is greater than about 0.13, greater than about 0.14, greater than about 0.15, greater than about 0.16, greater than about 0.17, or even higher.
  • an external medium 99 e.g., ambient air
  • near-field proximity of the MLR structure 320 to the active layer 314, and structural arrangement of the MLR structure 320 (and one or both of a dielectric layer 306 or an additional MLR structure 321 , if present), can result in a fraction of output light propagating within the diode structure 310 toward the front surface of the first semiconductor layer 311 , within an escape cone defined by an interface between the first semiconductor layer 311 and a substantially transparent solid medium 99 (e.g., silicone or sapphire), that is greater than about 0.35, greater than about 0.40, or even higher.
  • a substantially transparent solid medium 99 e.g., silicone or sapphire
  • one or both of the MLR structure 320 or the device exit surface 317 can be arranged so that the device 300 exhibits a mean total number of internal redirections and internal reflections per photon of output light, after being emitted by the active layer 314 and before exiting the diode structure 310 through the device exit surface 317, that is less than 30, less than 20, less than 10, or less than 5.
  • the light-emitting device 300 can exhibit a photon extraction efficiency that is greater than about 80.%, greater than about 90.%, or greater than about 95.%.
  • the MLR structure 320 (and one or both of a dielectric layer 306 or an additional MLR structure 321 , if present), or the MLR structure 320 with a metal layer 305 on its back surface, can exhibit reflectivity that is greater than about 80.%, greater than about 85.%, greater than about 90.%, or greater than about 95.%.
  • the MLR structure 320 (and one or both of a dielectric layer 306 or an additional MLR structure 321 , if present), or the MLR structure 320 with a metal layer 305 on its back surface, can exhibit optical loss per pass for output light incident thereon that is less than about 20.%, less than about 10.%, less than about 5.%, less than about 2.0%, or less than about 1 .0%.
  • arrangement of the device exit surface 317 can include an external medium 99 in direct contact with at least a portion of the front surface of the first semiconductor layer 311.
  • the device exit surface 317 can include an anti-reflection layer or coating 318 so that the device exit surface 317 against the external medium 99 exhibits reduced reflectivity, for output light perpendicularly incident thereon from within the diode structure 310, relative to Fresnel reflectivity of an interface between the front surface of the first semiconductor layer 311 and the external medium 99 in the absence of the front-surface coating or layer 318.
  • the anti-reflection layer or coating 318 can include a singlelayer quarter-wave dielectric thin film or a multi-layer dielectric thin film; in some examples the anti-reflection layer or coating 318 can include an array of nanoantennae, meta-atoms, or meta-molecules; in some examples the anti-reflection layer or coating 318 can include a moth-eye structure or an index-gradient film.
  • reflectivity of the device exit surface 317 against the external medium 99 can be less than about 10.%, less than about 5.%, less than about 2.0%, less than about 1 .0%, or less than about 0.5%.
  • the anti-reflection layer or coating can include one or more materials among: doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers.
  • the external medium 99 can be substantially solid and can include one or more materials among: one or more metal or semiconductor oxides, oxynitrides, or nitrides, one or more doped or undoped silicones, or one or more doped or undoped polymers; in some other examples the external medium 99 can comprise vacuum, air, a gaseous medium, or a liquid medium.
  • a method for making an inventive light-emitting device 300 can include: (A) forming the first semiconductor layer 311 , the active layer 314, and the second semiconductor layer 312; and (B) forming the MLR structure 320 on the back surface of the second semiconductor layer 312.
  • a method for making an inventive light-emitting device 300 can include: (A) forming the first semiconductor layer 311 , the active layer 314, and the second semiconductor layer 312; (B) forming the MLR structure 320 on the back surface of the second semiconductor layer 312; and (C) forming the metal layer 305 on the back surface of the MLR structure 320.
  • the method can further include forming the dielectric layer 306 on the back surface of the MLR structure 320 before forming the metal layer 305; in some of those examples the method can further include forming the additional MLR structure 321 on the dielectric layer 306 before forming the metal layer 305.
  • a method for making an inventive light-emitting device 300 can include: (A) forming the first semiconductor layer 311 , the active layer 314, and the second semiconductor layer 312; (B) forming the MLR structure 320 on the back surface of the second semiconductor layer 312; and (C) forming the plurality of optical scattering elements within one or more layers of the MLR structure 320.
  • a method for making an inventive light-emitting device 300 can include: (A) forming the first semiconductor layer 311 , the active layer 314, and the second semiconductor layer 312; (B) forming the MLR structure 320 on the back surface of the second semiconductor layer 312; and (C) forming the anti-reflection layer or coating 318 on the device exit surface 317.
  • Any suitable one or more material processing techniques or methodologies can be employed, including but not limited to beam or vapor deposition, lithography of any type, epitaxy, nanoimprinting, film or layer growth, and so forth.
  • a method for operating an inventive light-emitting device 300 can include supplying to the light-emitting device 300 electrical power so that the light-emitting device 300 emits device output light from the device exit surface 317 to propagate in an external medium 99 against the device exit surface 317.
  • Example 1 A semiconductor light-emitting device comprising: (a) a semiconductor diode structure including first and second doped semiconductor layers and an active layer between a back surface of the first semiconductor layer and a front surface of the second semiconductor layer, the active layer being arranged for emitting output light, resulting from electrical current flow through the device, at a nominal emission vacuum wavelength Xo to propagate within the diode structure; and (b) a multi-layer reflector (MLR) structure positioned against a back surface of the second semiconductor layer, the MLR structure including two or more layers of dielectric materials of two or more different refractive indices arranged collectively so as to reflect output light incident thereon from within the second semiconductor layer, the second semiconductor layer being sufficiently thin so that the MLR structure is in nearfield proximity to the active layer relative to the vacuum wavelength Xo, (c) at least a portion of a front surface of the first semiconductor layer being arranged as a device exit surface through which at least a portion of the output light, that propagates perpendicularly
  • Example 2 The device of Example 1 further comprising a metal layer on a back surface of the MLR structure so that the MLR structure is between the metal layer and the back surface of the semiconductor layer.
  • Example s The device of Example 2 further comprising one or more electrically conductive vias, each via being arranged as a localized, circumscribed electrical conduction path through the MLR structure between the metal layer and the second semiconductor layer.
  • Example 4 The device of any one of Examples 2 or 3, the metal layer including one or more of aluminum, silver, or gold.
  • Example 5 The device of any one of Examples 2 through 4 further comprising a substantially transparent dielectric layer between the metal layer and the MLR structure.
  • Example 6 The device of Example 5, the dielectric layer having a refractive index less than an average refractive index of the MLR structure.
  • Example 7 The device of any one of Examples 5 or 6, the dielectric layer including one or more materials among: doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers.
  • Example 8 The device of any one of Examples 1 through 7 further comprising a substantially transparent electrode layer between the MLR structure and the back surface of the second semiconductor layer.
  • Example 9 The device of Example 8 further comprising multiple electrically conductive vias, each via being arranged as a localized, circumscribed electrical conduction path through the MLR structure between the metal layer and the transparent electrode layer.
  • Example 10 The device of any one of Examples 8 or 9, the transparent electrode layer including one or more of indium tin oxide, indium zinc oxide, or one or more other transparent conductive oxides.
  • Example 11 The device of any one of Examples 1 through 10, distance between the active layer and the MLR structure being less than about Xo/n, less than about Xo/2n, less than about Xo/4n, or less than about Xo/1On, n being the effective refractive index of the second semiconductor layer.
  • Example 12 The device of any one of Examples 1 through 11 , Xo being greater than about 0.20 pm, greater than about 0.4 pm, greater than about 0.8 pm, less than about 10. pm, less than about 2.5 pm, or less than about 1.0 pm.
  • Example 13 The device of any one of Examples 1 through 12, the MLR structure being arranged as a distributed Bragg reflector (DBR).
  • DBR distributed Bragg reflector
  • Example 14 The device of any one of Examples 1 through 13, the MLR structure including one or more materials among: doped or undoped silicon; one or more doped or undoped lll-V, ll-VI, or Group IV semiconductors; doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers.
  • Example 15 The device of any one of Examples 1 through 14, the MLR structure including layers of titanium oxide or niobium oxide interleaved with layers of silica.
  • Example 16 The device of any one of Examples 5 through 15 further comprising an additional multi-layer reflector (MLR) structure between the metal layer and the dielectric layer.
  • MLR multi-layer reflector
  • Example 17 The device of Example 16, the dielectric layer having a refractive index less than an average refractive index of the additional MLR structure.
  • Example 18 The device of any one of Examples 16 or 17, the additional MLR structure being arranged as a distributed Bragg reflector (DBR).
  • DBR distributed Bragg reflector
  • Example 19 The device of any one of Examples 16 through 18, the additional MLR structure including one or more materials among: doped or undoped silicon; one or more doped or undoped lll-V, ll-VI, or Group IV semiconductors; doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers.
  • doped or undoped silicon one or more doped or undoped lll-V, ll-VI, or Group IV semiconductors
  • doped or undoped silicon oxide, nitride, or oxynitride one or more doped or undoped metal oxides, nitrides, or oxynitrides
  • one or more optical glasses or one or more doped or undoped polymers.
  • Example 20 The device of any one of Examples 16 through 19, the additional MLR structure including layers of titanium oxide or niobium oxide interleaved with layers of silica.
  • Example 21 The device of any one of Examples 1 through 20 further comprising a plurality of optical scattering elements arranged within one or more layers of the MLR structure so as to scatter at least a portion of output light, that propagates laterally within the diode structure relative to the device exit surface, to propagate perpendicularly relative to the device exit surface.
  • Example 22 The device of Example 21 , the scattering elements including one or more volumes of dielectric material within one or more corresponding layers of the MLR structure, the dielectric material of each one of those scattering elements differing from material of the corresponding layer of the MLR structure with respect to refractive index.
  • Example 23 The device of any one of Examples 21 or 22, the scattering elements including one or more volumes of metallic material within one or more corresponding layers of the MLR structure.
  • Example 24 The device of any one of Examples 21 through 23, the scattering elements including one or more nano-antennae or one or more meta-atoms or metamolecules within one or more layers of the MLR structure.
  • Example 25 The device of any one of Examples 21 through 24, size of or spacing between scattering elements being less than about o/n, less than about Xo/2n, less than about Xo/4n, or less than about o/1On, n being the effective refractive index of the second semiconductor layer.
  • Example 26 The device of any one of Examples 21 through 25, the scattering elements including one or more materials among: one or more metals or metal alloys; doped or undoped silicon; one or more doped or undoped lll-V, ll-VI, or Group IV semiconductors; doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers.
  • Example 27 The device of any one of Examples 21 through 26, the MLR structure including layers of titanium oxide or niobium oxide interleaved with layers of silica, and the scattering elements including one or both of (i) titanium oxide or niobium oxide elements within one or more of the silica layers, or (ii) silica scattering elements within one or more of the titanium oxide or niobium oxide layers.
  • Example 28 The device of any one of Examples 21 through 27, the scattering elements being arranged within one or more corresponding layers of the MLR structure as a corresponding periodic array within the corresponding layer of the MLR structure.
  • Example 29 The device of Example 28, the one or more periodic arrays including one or more of a rectangular, hexagonal, or trigonal array.
  • Example 30 The device of any one of Examples 21 through 29, the scattering elements being arranged within one or more corresponding layers of the MLR structure in an irregular or aperiodic arrangement.
  • Example 31 The device of any one of Examples 1 through 30, near-field proximity of the MLR structure to the active layer, and structural arrangement of the MLR structure, resulting in the device exhibiting a Purcell factor that is greater than about 1 .01 , greater than about 1 .02, greater than about 1.03, greater than about 1.04, or greater than about 1.05.
  • Example 32 The device of any one of Examples 1 through 31 , near-field proximity of the MLR structure to the active layer, and structural arrangement of the MLR structure, resulting in a fraction of output light propagating within the diode structure toward the front surface of the first semiconductor layer, within an escape cone defined by an interface between the first semiconductor layer and an external medium against the front surface thereof, that is greater than about 0.13, greater than about 0.14, greater than about 0.15, greater than about 0.16, or greater than about 0.17.
  • Example 33 The device of Example 32, the external medium comprising ambient air.
  • Example 34 The device of any one of Examples 1 through 33, near-field proximity of the MLR structure to the active layer, and structural arrangement of the MLR structure, resulting in a fraction of output light propagating within the diode structure toward the front surface of the first semiconductor layer, within an escape cone defined by an interface between the first semiconductor layer and a substantially transparent solid medium against the front surface thereof, that is greater than about 0.35 or greater than about 0.40.
  • Example 35 The device of any one of Examples 1 through 34, one or both of the MLR structure or the device exit surface being arranged so that the device exhibits a mean total number of internal redirections and internal reflections per photon of output light, after being emitted by the active layer and before exiting the diode structure through the device exit surface, that is less than 30, less than 20, less than 10, or less than 5.
  • Example 36 The device of any one of Examples 1 through 35, the lightemitting device exhibiting a photon extraction efficiency that is greater than about 80.%, greater than about 90.%, or greater than about 95.%.
  • Example 37 The device of any one of Examples 1 through 36, the MLR structure, or the MLR structure with a metal layer on a back surface thereof, exhibiting reflectivity that is greater than about 80.%, greater than about 85.%, greater than about 90.%, or greater than about 95.%.
  • Example 38 The device of any one of Examples 1 through 37, the MLR structure, or the MLR structure with a metal layer on a back surface thereof, exhibiting optical loss per pass for output light incident thereon that is less than about 20.%, less than about 10.%, less than about 5.%, less than about 2.0%, or less than about 1 .0%.
  • Example 39 The device of any one of Examples 1 through 38, wherein arrangement of the device exit surface includes an external medium in direct contact with at least a portion of the front surface of the first semiconductor layer.
  • Example 40 The device of any one of Examples 1 through 38, the device exit surface including an anti-reflection layer or coating so that the device exit surface against an external medium exhibits reflectivity for output light perpendicularly incident thereon from within the diode structure that is less than Fresnel reflectivity of an interface between the front surface of the first semiconductor layer and the external medium without the front-surface coating or layer.
  • Example 41 The device of Example 40, the anti-reflection layer or coating including a single-layer quarter-wave dielectric thin film or a multi-layer dielectric thin film.
  • Example 42 The device of Example 40, the anti-reflection layer or coating including an array of nano-antennae, meta-atoms, or meta-molecules.
  • Example 43 The device of Example 40, the anti-reflection layer or coating including a moth-eye structure or an index-gradient film.
  • Example 44 The device of any one of Examples 40 through 43, reflectivity of the device exit surface against the external medium being less than about 10.%, less than about 5.%, less than about 2.0%, less than about 1 .0%, or less than about 0.5%.
  • Example 45 The device of any one of Examples 40 through 44, the antireflection layer or coating including one or more materials among: doped or undoped silicon oxide, nitride, or oxynitride; one or more doped or undoped metal oxides, nitrides, or oxynitrides; one or more optical glasses; or one or more doped or undoped polymers.
  • Example 46 The device of any one of Examples 40 through 45, the front surface of the diode structure being positioned against the external medium, the external medium being substantially solid and including one or more materials among: one or more metal or semiconductor oxides, oxynitrides, or nitrides, one or more doped or undoped silicones, or one or more doped or undoped polymers.
  • Example 47 The device of any one of Examples 40 through 45, the external medium comprising vacuum, air, a gaseous medium, or a liquid medium.
  • Example 48 The device of any one of Examples 1 through 47, the entire front surface of the first semiconductor layer being arranged as the device exit surface.
  • Example 49 The device of any one of Examples 1 through 47, only a first portion of the front surface of the first semiconductor layer being arranged as the device output surface, and a second portion of the front surface of the first semiconductor layer being arranged so as to exhibit specular or non-specular internal reflective redirection of output light incident on the front surface of the first semiconductor layer from within the diode structure.
  • Example 50 The device of any one of Examples 1 through 49, the semiconductor diode structure comprising a semiconductor light-emitting diode.
  • Example 51 The device of any one of Examples 1 through 50, the diode structure including one or more doped or undoped lll-V, ll-VI, or Group IV semiconductor materials or alloys or mixtures thereof.
  • Example 52 The device of any one of Examples 1 through 51 , the active layer including one or more doped or undoped lll-V, ll-VI, or Group IV semiconductor materials or alloys or mixtures thereof.
  • Example 53 The device of any one of Examples 1 through 52, the active layer including one or more p-n junctions, one or more quantum wells, one or more multi-quantum wells, or one or more quantum dots.
  • Example 54 A method for making the light-emitting device of any one of Examples 1 through 53, the method comprising: (A) forming the first semiconductor layer, the active layer, and the second semiconductor layer; and (B) forming the MLR structure on the back surface of the second semiconductor layer.
  • Example 55 A method for making the light-emitting device of any one of Examples 2 through 53, the method comprising: (A) forming the first semiconductor layer, the active layer, and the second semiconductor layer; (B) forming the MLR structure on the back surface of the second semiconductor layer; and (C) forming the metal layer on the back surface of the MLR structure.
  • Example 56 A method for making the light-emitting device of any one of Examples 5 through 53, the method comprising: (A) forming the first semiconductor layer, the active layer, and the second semiconductor layer; (B) forming the MLR structure on the back surface of the second semiconductor layer; (C) forming the dielectric layer on the back surface of the MLR structure; and (D) forming the metal layer on the back surface of the MLR structure. [0102]
  • Example 57 A method for making the light-emitting device of any one of Examples 5 through 53, the method comprising: (A) forming the first semiconductor layer, the active layer, and the second semiconductor layer; (B) forming the MLR structure on the back surface of the second semiconductor layer; (C) forming the dielectric layer on the back surface of the MLR structure; and (D) forming the metal layer on the back surface of the MLR structure.
  • a method for making the light-emitting device of any one of Examples 16 through 53 comprising: (A) forming the first semiconductor layer, the active layer, and the second semiconductor layer; (B) forming the MLR structure on the back surface of the second semiconductor layer; (C) forming the dielectric layer on the back surface of the MLR structure; (D) forming the additional MLR structure on the dielectric layer; and (E) forming the metal layer on the additional MLR structure.
  • Example 58 A method for making the light-emitting device of any one of Examples 21 through 53, the method comprising: (A) forming the first semiconductor layer, the active layer, and the second semiconductor layer; (B) forming the MLR structure on the back surface of the second semiconductor layer; and (C) forming the plurality of optical scattering elements within one or more layers of the MLR structure.
  • Example 59 A method for making the light-emitting device of any one of Examples 40 through 53, the method comprising: (A) forming the first semiconductor layer, the active layer, and the second semiconductor layer; (B) forming the MLR structure on the back surface of the second semiconductor layer; and (C) forming the anti-reflection layer or coating on the device exit surface.
  • Example 60 A method for operating the light-emitting device of any one of Examples 1 through 53, the method comprising supplying to the light-emitting device electrical power so that the light-emitting device emits device output light from the device exit surface to propagate in an external medium against the device exit surface.
  • each of “a dog, a cat, or a mouse,” “one or more of a dog, a cat, or a mouse,” and “one or more dogs, cats, or mice” would be interpreted as (i) one or more dogs without any cats or mice, (ii) one or more cats without and dogs or mice, (iii) one or more mice without any dogs or cats, (iv) one or more dogs and one or more cats without any mice, (v) one or more dogs and one or more mice without any cats, (vi) one or more cats and one or more mice without any dogs, or (vii) one or more dogs, one or more cats, and one or more mice.
  • each of “two or more of a dog, a cat, or a mouse” or “two or more dogs, cats, or mice” would be interpreted as (i) one or more dogs and one or more cats without any mice, (ii) one or more dogs and one or more mice without any cats, (iii) one or more cats and one or more mice without and dogs, or (iv) one or more dogs, one or more cats, and one or more mice; “three or more,” “four or more,” and so on would be analogously interpreted.
  • each such phrase shall denote the case wherein the quantity in question has been reduced or diminished to such an extent that, for practical purposes in the context of the intended operation or use of the disclosed or claimed apparatus or method, the overall behavior or performance of the apparatus or method does not differ from that which would have occurred had the null quantity in fact been completely removed, exactly equal to zero, or otherwise exactly nulled.
  • any labelling of elements, steps, limitations, or other portions of an embodiment, example, or claim e.g., first, second, third, etc., (a), (b), (c), etc., or (i), (ii), (iii), etc.) is only for purposes of clarity, and shall not be construed as implying any sort of ordering or precedence of the portions so labelled. If any such ordering or precedence is intended, it will be explicitly recited in the embodiment, example, or claim or, in some instances, it will be implicit or inherent based on the specific content of the embodiment, example, or claim.

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Abstract

Un dispositif électroluminescent comprend une structure de diode à semi-conducteur et une structure de réflecteur multicouche (MLR). La structure de diode comprend des première et seconde couches semi-conductrices dopées et une couche active entre elles ; la couche active émet une lumière de sortie à une longueur d'onde de vide d'émission nominale λ0 pour qu'elle se propage à l'intérieur de la structure de diode. La structure MLR est positionnée contre une surface arrière de la seconde couche semi-conductrice, comprend au moins deux couches de matériaux diélectriques ayant au moins deux indices de réfraction différents, réfléchit la lumière de sortie incidente à l'intérieur de la structure de diode, et est à proximité du champ proche de la couche active par rapport à λ0. Au moins une partie de la lumière de sortie, se propageant perpendiculairement à l'intérieur de la structure de diode par rapport à une surface de sortie de dispositif, sort de la structure de diode en tant que lumière de sortie de dispositif. La structure MLR peut comprendre des éléments de diffusion qui diffusent une partie de la lumière de sortie se propageant latéralement pour qu'elle se propage perpendiculairement.
PCT/US2022/039377 2021-08-13 2022-08-04 Dispositif électroluminescent à semi-conducteur avec réflecteur multicouche en champ proche WO2023018592A1 (fr)

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EP22761762.8A EP4385074A1 (fr) 2021-08-13 2022-08-04 Dispositif électroluminescent à semi-conducteur avec réflecteur multicouche en champ proche
CN202280069243.3A CN118103998A (zh) 2021-08-13 2022-08-04 具有近场多层反射器的半导体发光器件

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US17/879,948 US20230051992A1 (en) 2021-08-13 2022-08-03 Semiconductor light-emitting device with near-field multi-layer reflector

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