Abstract: To improve the luminous efficiency of a UV light-emitting device, the UV light-emitting devices disclosed herein have an AlGaN-based crystal or an InAlGaN-based crystal, and comprise an emission layer, at least one electron blocking layer, a first p-type doped layer, and a composition gradient layer in which the Al composition ratio varies depending on the position over a thickness direction of the layer stack, stacked in this order in the direction of the flow of electrons. The Al composition ratio varies depending on the position over the thickness direction in the composition gradient layer. The UV light-emitting devices are implemented as UV-region light-emitting diodes and laser diodes.

Abstract: A deep ultraviolet LED with a design wavelength ?, including a reflecting electrode layer (Au), a metal layer (Ni), a p-GaN contact layer, a p-block layer made of a p-AlGaN layer, an i-guide layer made of an AlN layer, a multi-quantum well layer, an n-AlGaN contact layer, a u-AlGaN layer, an AlN template, and a sapphire substrate that are arranged in this order from a side opposite to the sapphire substrate, in which the thickness of the p-block layer is 52 to 56 nm, a two-dimensional reflecting photonic crystal periodic structure having a plurality of voids is provided in a region from the interface between the metal layer and the p-GaN contact layer to a position not beyond the interface between the p-GaN contact layer and the p-block layer in the thickness direction of the p-GaN contact layer, the distance from an end face of each of the voids in the direction of the sapphire substrate to the interface between the multi-quantum well layer and the i-guide layer satisfies ?/2n1Deff (where ? is the design wav

Abstract: A deep ultraviolet LED with a design wavelength ?, including a reflecting electrode layer (Au), a metal layer (Ni), a p-GaN contact layer, a p-block layer made of a p-AlGaN layer, an i-guide layer made of an AlN layer, a multi-quantum well layer, an n-AlGaN contact layer, a u-AlGaN layer, an AlN template, and a sapphire substrate that are arranged in this order from a side opposite to the sapphire substrate, in which the thickness of the p-block layer is 52 to 56 nm, a two-dimensional reflecting photonic crystal periodic structure having a plurality of voids is provided in a region from the interface between the metal layer and the p-GaN contact layer to a position not beyond the interface between the p-GaN contact layer and the p-block layer in the thickness direction of the p-GaN contact layer, the distance from an end face of each of the voids in the direction of the sapphire substrate to the interface between the multi-quantum well layer and the i-guide layer satisfies ?/2n1Deff (where ? is the design wav

Abstract: Provided is a deep ultraviolet LED with a design wavelength ?, including an Al reflecting electrode layer, an ultrathin metal layer, and a transparent p-AlGaN contact layer that are sequentially arranged from a side opposite to a substrate, and a photonic crystal periodic structure provided in the range of the thickness direction of the transparent p-AlGaN contact layer. The photonic crystal periodic structure has a photonic band gap.

Abstract: A deep ultraviolet LED with a design wavelength of ? is provided that includes a reflecting electrode layer, a metal layer, a p-type GaN contact layer, and a p-type AlGaN layer that are sequentially stacked from a side opposite to a substrate, the p-type AlGaN layer being transparent to light with the wavelength of ?; and a photonic crystal periodic structure that penetrates at least the p-type GaN contact layer and the p-type AlGaN layer. The photonic crystal periodic structure has a photonic band gap.

Abstract: To improve light extraction efficiency of a deep ultraviolet light-emitting diode (DUVLED), a typical LED element has a single crystal substrate made of sapphire or AlN, The ultraviolet layer is arranged as a film stack having an n-type conductive layer, a recombination layer, and a p-type conductive layer. A stack of a p-type contact layer and a reflective electrode is disposed on the p-type conductive layer. The ultraviolet emission layer and a p-type contact layer are made of mixed crystal of AlN and GaN. The transmittance for the emission wavelength of the p-type contact layer is increased, and the light extraction efficiency is improved. Also an LED element whose p-type contact layer is configured in a layered structure and whose reflective electrode is patterned is provided. Moreover, an electric appliance having such LED elements is provided.

Abstract: To improve light extraction efficiency of a deep ultraviolet light-emitting diode (DUVLED), a typical LED element has a single crystal substrate made of sapphire or AlN, The ultraviolet layer is arranged as a film stack having an n-type conductive layer, a recombination layer, and a p-type conductive layer. A stack of a p-type contact layer and a reflective electrode is disposed on the p-type conductive layer. The ultraviolet emission layer and a p-type contact layer are made of mixed crystal of AlN and GaN. The transmittance for the emission wavelength of the p-type contact layer is increased, and the light extraction efficiency is improved. Also an LED element whose p-type contact layer is configured in a layered structure and whose reflective electrode is patterned is provided. Moreover, an electric appliance having such LED elements is provided.