Group-III nitride semiconductor light-emitting device
AssigneeShowa Denko K.K.
InventorTakashi Udagawa
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Abstract
Light-emitting device with excellent emission intensity is difficult to obtain when gallium indium nitride with high indium composition ratio and poor crystallinity is employed as active layer for group-III nitride light-emitting device to emit a comparatively long wavelength light. The invention provides a light-emitting layer on a super lattice structure as a base layer, and crystallinity of the light-emitting layer is then improved. Furthermore, abruptness of a crystal composition at an interface of the light-emitting layer and an upper junction layer is achieved, thus forming a bending portion of a band structure expedient for allowing the emitting-layer to emit a light with a long wavelength.
Claims8
A group-III nitride semiconductor light-emitting device which takes a pn-junction type double hetero (DH) junction structure which comprises an n-type cladding layer and a p-type cladding layer formed on one surface of a single crystal substrate, and a light-emitting layer made of a group-III nitride semiconductor crystal layer provided between the n and p-type cladding layers, wherein the light-emitting layer includes a super lattice structure in which n-type group-III nitride semiconductor crystal layers disposed closer to the n-type cladding layer are alternately stacked repeatingly, the n-type group-III nitride semiconductor crystal layers having different composition ratios of a group-III constituent element and approximately the same thickness and the stacking cycle number ranging from two pairs to twenty five pairs;
- and an active layer made of an n-type group-III nitride semiconductor crystal layer provided on a layer as an upper end layer which is located at an end of the super lattice structure closer to the p-type cladding layer, the n-type group-III nitride semiconductor crystal layer having a non-rectangular potential structure due to a bend of a band.
Dependencies are inferred from the claim text.