A light-emitting device includes a photoluminescent layer that emits light containing first light, a light-transmissive layer located on or near the photoluminescent layer, a low-refractive-index layer and a high-refractive-index layer. A submicron structure is defined on the photoluminescent layer and/or the light-transmissive layer. The low-refractive-index layer is located on or near the photoluminescent layer so that the photoluminescent layer is located between the low-refractive-index layer and light-transmissive layer. The high-refractive-index layer is located on or near the low-refractive-index layer so that the low-refractive-index layer is located between the high-refractive-index layer and the photoluminescent layer. The submicron structure includes at least projections or recesses and satisfies the following relationship:
.sub.a/n.sub.wav-a<D.sub.int<.sub.a
where D.sub.int is the center-to-center distance between adjacent projections or recesses, .sub.a is the wavelength of the first light in air, and n.sub.wav-a is the refractive index of the photoluminescent layer for the first light.

A light-emitting diode module for emitting white light includes a first light emitting diode chip for generating radiation in the blue spectral range having a first peak wavelength, a second light emitting diode chip for generating radiation in the blue spectral range having a second peak wavelength, a third light emitting diode chip for generating radiation in the red spectral range having a third peak wavelength, a first and a second phosphors disposed downstream of the first and the second light emitting diode chips, respectively. The first light emitting diode chip with the first phosphor generates a first mixed radiation and the second light emitting diode chip with the second phosphor generates a second mixed radiation. The first phosphor exhibits a first absorption maximum at a wavelength greater than the first peak wavelength. The second phosphor exhibits a second absorption maximum at a wavelength less than the second peak wavelength.

A light-emitting device is provided. The light-emitting device comprises a light-emitting stack comprising a first semiconductor layer, a second semiconductor layer and an active layer between the first semiconductor layer and the second semiconductor layer. The light-emitting device further comprises a third semiconductor layer on the light-emitting stack and comprising a first sub-layer, a second sub-layer and a roughened surface, wherein the first sub-layer has the same composition as that of the second sub-layer, and the composition of the first sub-layer is with a different atomic ratio from that of the second sub-layer. A method for manufacturing the light-emitting device is also provided.

A light emitting device can include a supporting layer; a semiconductor structure including: an active layer between first-type and second-type semiconductor layers, a first top surface and a first bottom surface, and a side surface between the first top and bottom surfaces, which is inclined; a first electrode between the supporting and semiconductor layers; a connection metal layer having a first portion between the first electrode and the supporting layer, which includes a stepped portion having a upper portion contacting the first electrode, and a second portion of the connection metal layer extends beyond the semiconductor structure; and a passivation layer extending from the second portion of the connection metal layer to the side surface of the semiconductor structure, which includes a second bottom surface contacting the second portion of the connection metal layer; and a second top surface opposite to the second bottom surface.

A method of fabricating a flip-chip photonic-crystal light-emitting diode (LED) is disclosed. The method includes the steps of: providing an initial substrate including an epitaxial-growth surface and a light-output surface; performing a nanoimprint process on the epitaxial-growth surface of the initial substrate to form a nano-level patterned substrate; forming a flip-chip LED structure on the epitaxial-growth surface of the nano-level patterned substrate; and performing a nanoimprint process on the light-output surface of the nano-level patterned substrate to form the flip-chip photonic-crystal LED. The formation of the photonic-crystal structure on the light-output surface results in enhanced LED light extraction and emission efficiency.

A light-emitting diode including a support substrate, a semiconductor stack disposed on the support substrate and including a p-type compound semiconductor layer, an active layer, and an n-type compound semiconductor layer, a reflective metal layer disposed between the support substrate and the semiconductor stack, the reflective metal layer being in ohmic contact with the p-type compound semiconductor layer of the semiconductor stack and including a groove exposing a portion of the semiconductor stack, an insulation layer disposed between the support substrate and the semiconductor stack and disposed in the groove, and a first electrode including a first electrode pad and a first electrode extension and contacting the n-type compound semiconductor layer of the semiconductor stack, in which the first electrode extension is connected to the first electrode pad, and the first electrode extension is formed along an outer boundary of the light-emitting diode.

A quantum dot includes a seed and a core enclosing the seed. The core is grown from the seed to improve size uniformity of the core. The seed includes a first compound without Cd. The first compound may be GaP. The core may include a second compound including elements from group XIII and group XV. The second compound may be InP. The quantum dot may also include a first shell of a third compound enclosing the core. The third compound may be ZnSe or ZnS. The quantum dot may also include a second shell of a fourth compound enclosing the first shell. The fourth compound may be ZnS when the third compound is ZnSe. Embodiments also relate to a quantum dot including first to third elements selected from XIII group elements and XV group elements and fourth to sixth elements selected from XII group elements and XVI group elements.

A quantum dot includes a seed and a core enclosing the seed. The core is grown from the seed to improve size uniformity of the core. The seed includes a first compound without Cd. The first compound may be GaP. The core may include a second compound including elements from group XIII and group XV. The second compound may be InP. The quantum dot may also include a first shell of a third compound enclosing the core. The third compound may be ZnSe or ZnS. The quantum dot may also include a second shell of a fourth compound enclosing the first shell. The fourth compound may be ZnS when the third compound is ZnSe. Embodiments also relate to a quantum dot including first to third elements selected from XIII group elements and XV group elements and fourth to sixth elements selected from XII group elements and XVI group elements.

A profiled surface for improving the propagation of radiation through an interface is provided. The profiled surface includes a set of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation. The set of large roughness components can include a series of truncated shapes. The profiled surface also includes a set of small roughness components superimposed on the set of large roughness components and providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation.

A nitride semiconductor light-emitting element includes an N-type cladding layer, an N-side guide layer, an active layer, a P-type cladding layer, and a P-side guide layer (an upper P-side guide layer) and an electron blocking layer that are disposed between the active layer and the P-type cladding layer. The N-type cladding layer, the N-side guide layer, the P-side guide layer, the electron blocking layer, and the P-type cladding layer contains Al. The active layer includes an N-side barrier layer, a well layer disposed above the N-side barrier layer, and a P-side barrier layer disposed above the well layer. The average band gap energy of the P-side barrier layer is greater than the average band gap energy of the N-side barrier layer. A thickness of the P-side barrier layer is less than a thickness of the N-side barrier layer.