Patent ID: 8785904

Claim:
A light-emitting device comprising: a two-dimensional electron gas (2DEG) structure; an n-type layer formed on the two-dimensional electron gas structure; a p-type layer; an active region sandwiched between the n-type layer and the p-type layer; a p-contact electrically connected to the p-type layer; and an n-contact electrically connected to the n-type layer, wherein the n-type layer has a stepped structure with an upper step surface and a lower step surface being connected by a sidewall, and the n-contact is conformably formed on the upper step surface, the lower step surface and the sidewall of the stepped structure of the n-type layer; wherein the two-dimensional electron gas structure comprises one or more pairs of n-type GaN layers and n-type AlGaN layers, each of the one of more pairs of n-type GaN layer and n-type AlGaN layer is so selected that an interface thereof defines a 2DEG channel, thus the one or more pairs of n-type GaN layers and n-type AlGaN layers form one or more 2DEG channels, a plurality of discontinuities are formed in the two-dimensional electron gas structure exposing the one or more 2DEG channels, and the n-type layer is formed on the two-dimensional electron gas structure and in electrical contact with the one or more 2DEG channels through the plurality of discontinuities.