Ultraviolet light emitting element and electrical device using same

An ultraviolet light emitting element, comprising:

• a sapphire substrate;
• an n-type AlGaN layer;
• a light emitting layer;
• a cap layer;
• an electron barrier layer;
• and
• a p-type contact layer including a p-type GaN layer,
• wherein
• the light emitting layer has a multi-quantum well structure,
• the multi-quantum well structure includes
• a plurality of barrier layers each being a first AlGaN layer and
• a plurality of well layers each being a second AlGaN layer,
• the electron barrier layer includes
• at least one first p-type AlGaN layer having an Al composition ratio higher than an Al composition ratio of each of the barrier layers and
• at least one second p-type AlGaN layer having an Al composition ratio higher than an Al composition ratio of each of the plurality of well layers and lower than the Al composition ratio of the at least one first p-type AlGaN layer,
• the at least one first p-type AlGaN layer and the at least one second p-type AlGaN layer contain Mg,
• the cap layer is located between one well layer of the plurality of well layers of the multi-quantum well structure and the at least one first p-type AlGaN layer, the one well layer being closest to the at least one first p-type AlGaN layer,
• the cap layer is a third AlGaN layer having an Al composition ratio higher than the Al composition ratio of each of the plurality of well layers and lower than the Al composition ratio of the at least one first p-type AlGaN layer, and
• the cap layer has a thickness of greater than or equal to 1 nm and less than or equal to 7 nm;
• and
• the at least one first p-type AlGaN layer including a plurality of first p-type AlGaN layers and the at least one second p-type AlGaN layer of the electron barrier layer are alternately arranged in a thickness direction of the light emitting layer.

An ultraviolet light emitting element, comprising:

• a sapphire substrate;
• an n-type AlGaN layer;
• a light emitting layer;
• a cap layer;
• an electron barrier layer;
• and
• a p-type contact layer including a p-type GaN layer,
• wherein
• the light emitting layer has a multi-quantum well structure,
• the multi-quantum well structure includes
• a plurality of barrier layers each being a first AlGaN layer and
• a plurality of well layers each being a second AlGaN layer,
• the electron barrier layer includes
• at least one first p-type AlGaN layer having an Al composition ratio higher than an Al composition ratio of each of the barrier layers and
• at least one second p-type AlGaN layer having an Al composition ratio higher than an Al composition ratio of each of the plurality of well layers and lower than the Al composition ratio of the at least one first p-type AlGaN layer,
• the at least one first p-type AlGaN layer and the at least one second p-type AlGaN layer contain Mg,
• the cap layer is located between one well layer of the plurality of well layers of the multi-quantum well structure and the at least one first p-type AlGaN layer, the one well layer being closest to the at least one first p-type AlGaN layer,
• the cap layer is a third AlGaN layer having an Al composition ratio higher than the Al composition ratio of each of the plurality of well layers and lower than the Al composition ratio of the at least one first p-type AlGaN layer, and
• the cap layer has a thickness of greater than or equal to 1 nm and less than or equal to 7 nm;
• in a multilayer structure including the n-type AlGaN layer, the light emitting layer, the cap layer, the electron barrier layer, and the p-type contact layer, the n-type AlGaN layer, the light emitting layer, the cap layer, the electron barrier layer, and the p-type contact layer are arranged in this order from a side close to the sapphire substrate, and
• the ultraviolet light emitting element includes a buffer layer between the sapphire substrate and the n-type AlGaN layer, the buffer layer including an AlxGa1−xN layer, where 0<×≦1, and
• a full width at half maximum of an X-ray rocking curve obtained by ω scan X-ray diffraction on a (10-12) plane of the AlxGa1−xN layer is less than or equal to 400 arcsec, where 0<×≦1.

An ultraviolet light emitting element, comprising:

• a sapphire substrate;
• an n-type AlGaN layer;
• a light emitting layer;
• a cap layer;
• an electron barrier layer;
• and
• a p-type contact layer including a p-type GaN layer,
• wherein
• the light emitting layer has a multi-quantum well structure,
• the multi-quantum well structure includes
• a plurality of barrier layers each being a first AlGaN layer and
• a plurality of well layers each being a second AlGaN layer,
• the electron barrier layer includes
• at least one first p-type AlGaN layer having an Al composition ratio higher than an Al composition ratio of each of the barrier layers and
• at least one second p-type AlGaN layer having an Al composition ratio higher than an Al composition ratio of each of the plurality of well layers and lower than the Al composition ratio of the at least one first p-type AlGaN layer,
• the at least one first p-type AlGaN layer and the at least one second p-type AlGaN layer contain Mg,
• the cap layer is located between one well layer of the plurality of well layers of the multi-quantum well structure and the at least one first p-type AlGaN layer, the one well layer being closest to the at least one first p-type AlGaN layer,
• the cap layer is a third AlGaN layer having an Al composition ratio higher than the Al composition ratio of each of the plurality of well layers and lower than the Al composition ratio of the at least one first p-type AlGaN layer, and
• the cap layer has a thickness of greater than or equal to 1 nm and less than or equal to 7 nm;
• each of the barrier layers has a thickness of greater than or equal to 2 nm and less than or equal to 20 nm, and
• each of the barrier layers is doped with Si, a concentration of the Si being greater than or equal to 5×1017 cm−3 and less than or equal to 5×1018 cm−3.