Panasonic Corporation

Riken Corporation

Panasonic Electric Works Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Takayoshi Takano

Hideki Hirayama

Kenji Tsubaki

Norimichi Noguchi

Takuya Mino

Jun Sakai

Sachie Fujikawa

Yukihiro Kondo

Hitomichi Takano

Masafumi Jo

Junji Ikeda

An ultraviolet light-emitting element includes: a multilayer stack in which an n-type AlGaN layer, a light-emitting layer, a first p-type AlGaN layer, and a second p-type AlGaN layer are arranged in this order; a negative electrode; and a positive electrode. The first p-type AlGaN layer has a larger Al composition ratio than first AlGaN layers serving as well layers. The second p-type AlGaN layer has a larger Al composition ratio than the first AlGaN layers. The first p-type AlGaN layer and the second p-type AlGaN layer both contain Mg. The second p-type AlGaN layer has a higher maximum Mg concentration than the first p-type AlGaN layer. The second p-type AlGaN layer includes a region where an Mg concentration increases in a thickness direction thereof as a distance from the first p-type AlGaN layer increases in the thickness direction.

Ultraviolet light-emitting element

An epitaxial substrate includes: a single crystal substrate including projections arranged in an array on a plane. Each projection has a conical or pyramidal shape tapered in a normal direction to the plane. The AlN layer includes: a first AlN crystal covering the plane and the projections with tips of the projections being exposed; second AlN crystals protruding from the tips of the projections along the normal direction and each having a shape of a column whose cross-sectional area increases as a distance from a tip of a corresponding projection increases; and a third AlN crystal as a layer interconnecting ends of the second AlN crystals, opposite the single crystal substrate.

Epitaxial substrate

A UV LED element, which is an exemplary ultraviolet light-emitting diode according to the present invention, includes an n-type conductive layer, a light-emitting layer, an electron block layer, and a p-type contact layer, all of which are arranged in this order. Bandgap energy of the electron block layer satisfies E&#x2264;E, where Edesignates bandgap energy of the p-type contact layer and Edesignates the bandgap energy of the electron block layer. The electric apparatus includes the UV LED element as a light source for emitting an ultraviolet ray.

Ultraviolet light-emitting diode and electric apparatus provided with the same

An ultraviolet light emitting element includes a light emitting layer, a cap layer, an electron barrier layer. The light emitting layer has a multi-quantum well structure including barrier layers each including a first AlGaN layer and well layers each including a second AlGaN layer. The electron barrier layer includes at least one first p-type AlGaN layer and at least one second p-type AlGaN layer. The cap layer is located between the first p-type AlGaN layer and one of the well layers closest to the first p-type AlGaN layer. The cap layer is a third AlGaN layer having an Al composition ratio greater than an Al composition ratio of each of the well layers and less than an Al composition ratio of the first p-type AlGaN layer. The cap layer has a thickness of greater than or equal to 1 nm and less than or equal to 7 nm.

Ultraviolet light emitting element and electrical device using same

In a method of manufacture for a nitride semiconductor light emitting element including: a monocrystalline substrate; and an AlN layer; and a first nitride semiconductor layer of a first electrical conductivity type; and a light emitting layer made of an AlGaN-based material; and a second nitride semiconductor layer of a second electrical conductivity type, a step of forming the AlN layer includes: a first step of supplying an Al source gas and a N source gas into the reactor to generate a group of AlN crystal nuclei having Al-polarity to be a part of the AlN layer on the surface of the monocrystalline substrate; and a second step of supplying the Al source gas and the N source gas into the reactor to form the AlN layer, after the first step.

Method of manufacture for nitride semiconductor light emitting element, wafer, and nitride semiconductor light emitting element

An ultraviolet semiconductor light-emitting element comprises a light-emitting layer which is arranged between an n-type nitride semiconductor layer and a p-type nitride semiconductor layer, an n-electrode that is in contact with the n-type nitride semiconductor layer, and a p-electrode that is in contact with the p-type nitride semiconductor layer. The p-type nitride semiconductor layer is provided with a p-type contact layer that has a band gap smaller than that of the light-emitting layer and is in ohmic contact with the p-electrode. A depressed part is formed in a reverse side surface of a surface of the p-type nitride semiconductor layer that faces the light-emitting layer so as to avoid a formation region on which the p-electrode is formed. A reflective film that reflects ultraviolet light emitted from the light-emitting layer is formed on an inner bottom surface of the depressed part.

Ultraviolet semiconductor light-emitting element that emits ultraviolet light from one surface side

The nitride semi-conductive light emitting layer in this invention comprises a single crystal substratefor epitaxial growth, a first buffer layer, an n-type nitride semi-conductive layer, a second buffer layer, a third buffer layer, a light emitting layer, and a p-type nitride semi-conductive layer. The first buffer layeris laminated to a top side of the single crystal substrate. The n-type nitride semi-conductive layeris laminated to a top side of the first buffer layer. The third buffer layeris laminated to a top side of the n-type nitride semi-conductive layerwith the second buffer layerbeing interposed therebetween. The light emitting layeris laminated to a top side of the third buffer layer. The p-type nitride semi-conductive layeris laminated to a top side of the light emitting layer. The third buffer layerserves as a planarized base for growth of the light emitting layerso as to reduce a threading dislocation and a residual distortion in the light emitting layer. This nitride semi-conductive light emitting device reduces a piezoelectric field in the light emitting layer by exploiting carriers generated in the third buffer layer. The third buffer layeris doped with an Si impurity serving as a donor.

Nitride semi-conductive light emitting device

In a process of fabricating a nitride nitride semi-conductor layer of AlGaInN(0&#x3c;a&#x3c;1, 0&#x3c;b&#x3c;1, 1&#x2212;a&#x2212;b&#x3e;0), the AlGaInN layer is grown at a growth rate less than 0.09 &#x3bc;m/h according to the metal organic vapor phase epitaxy (MOPVE) method. The AlGaInN layer fabricated by the process in the present invention exhibits a high quality with low defect, and increases internal quantum yield.

Manufacturing method of nitride semi-conductor layer, and a nitride semi-conductor light emitting device with its manufacturing method

A nitride semi-conductor light emitting device has a p-type nitride semi-conductor layer, an n-type nitride semi-conductor layer, and a light emission layerwhich is interposed between the p-type nitride semi-conductor layerand the n-type nitride semi-conductor layer. The light emission layerhas a quantum well structure with a barrier layerand a well layer. The barrier layeris formed of AlGaInN (0&#x3c;a&#x3c;1, 0&#x3c;b&#x3c;1, 1&#x2212;a&#x2212;b&#x3e;0), and contains a first impurity at a concentration of A greater than zero. The well layeris formed of AlGaInN (0&#x3c;c&#x3c;1, c&#x3c;a, 0&#x3c;d&#x3c;1, 1&#x2212;c&#x2212;d&#x3e;0), and contains a second impurity at a concentration of B equal to or greater than zero. In the nitride semi-conductor light emitting device of the present invention, the concentration of A is larger than that of B, in order that the barrier layerhas a concentration of oxygen smaller than that in the well layer

Nitride semi-conductor light emitting device and a process of producing a nitride semi-conductor light emitting device

A semiconductor light emitting device includes an n-type nitride semiconductor layerformed on one surface side of a single-crystal substratefor epitaxial growth through a first buffer layer, an emission layerformed on a surface side of the n-type nitride semiconductor layer, and a p-type nitride semiconductor layerformed on a surface side of the emission layer. The emission layerhas an AlGaInN quantum well structure, and a second buffer layerhaving the same composition as a barrier layerof the emission layeris provided between the n-type nitride semiconductor layerand the emission layer. In the semiconductor light emitting device, it is possible to increase emission intensity of the ultraviolet radiation as compared with a conventional configuration while using AlGaInN as a material of the emission layer.

Growing community of inventors

Osaka, Japan

Takayoshi Takano