Rosestreet Labs Energy, Inc.

University of California

Iulian Gherasoiu

Wladyslaw Walukiewicz

Lothar Reichertz

A light emitting device includes a substrate, multiple n-type layers, and multiple p-type layers. The n-type layers and the p-type layers each include a group III nitride alloy. At least one of the n-type layers is a compositionally graded n-type group III nitride, and at least one of the p-type layers is a compositionally graded p-type group III nitride. A first ohmic contact for injecting current is formed on the substrate, and a second ohmic contact is formed on a surface of at least one of the p-type layers. Utilizing the disclosed structure and methods, a device capable of emitting light over a wide spectrum may be made without the use of phosphor materials.

Multi-color light emitting devices with compositionally graded cladding group III-nitride layers grown on substrates

A photovoltaic device having three dimensional (3D) charge separation and collection, where charge separation occurs in 3D depletion regions formed between a p-type doped group III-nitride material in the photovoltaic device and intrinsic structural imperfections extending through the material. The p-type group III-nitride alloy is compositionally graded to straddle the Fermi level pinning by the intrinsic structural imperfections in the material at different locations in the group III-nitride alloy. A field close to the surfaces of the intrinsic defects separates photoexcited electron-hole pairs and drives the separated electrons to accumulate at the surfaces of the intrinsic defects. The intrinsic defects function as n-type conductors and transport the accumulated electrons to the material surface for collection. The compositional grading also creates a potential that drives the accumulated separated electrons toward an n-type group III-nitride layer for collection. The p-type group III-nitride alloy may comprise an alloy of InGaN, InAlN or InGaAlN.

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Gilbert, AZ, United States of America

Iulian Gherasoiu