Pseudomorphic electronic and optoelectronic devices having planar contacts

摘要

In various embodiments, light-emitting devices incorporate smooth contact layers and polarization doping (i.e., underlying layers substantially free of dopant impurities) and exhibit high photon extraction efficiencies.

主权项

1. An ultraviolet (UV) light-emitting device comprising:
a substrate having an AlyGa1-yN top surface, wherein 1.0≧y≧0.4; a light-emitting device structure disposed over the substrate, the device structure comprising a plurality of layers each comprising AlxGa1-xN; an undoped graded Al1-zGazN layer disposed over the device structure, a composition of the graded layer being graded in Ga concentration z such that the Ga concentration z increases in a direction away from the light-emitting device structure; a p-doped Al1-wGawN cap layer disposed over the graded layer, the p-doped Al1-wGawN cap layer having a Ga concentration w, wherein 1.0≧w≧0.8; and a metallic contact disposed over the Al1-wGawN cap layer and comprising at least one metal.