Patent ID: 8035113

Claim:
A semiconductor device for use as an emitter, the device comprising: a substrate having a smooth surface and comprising a material selected from the group consisting of sapphire, silicon carbide, zinc oxide, silicon, gallium arsenide, gallium nitride, aluminum nitride and aluminum gallium nitride; a first layer grown on said substrate, said first layer having upper and lower surfaces, the lower surface grown onto and contacting the smooth surface of said substrate, the first layer comprising a III-nitride semiconductor, wherein the upper surface of the first layer is textured as grown, the texture resulting from the growth process, and the first layer being n-type doped; a first contact electrically connected to the first layer; one or more quantum well layers on respective barrier layers deposited directly on said first layer and textured by the upper surface of the first layer, the barrier layers comprising a III-nitride semiconductor and the quantum well layers comprising a III-nitride semiconductor; and an upper layer on said quantum well layers comprising a III-nitride semiconductor separated from the quantum well layers by a further barrier layer, wherein the upper layer and further barrier layer are surface textured by the surface of the adjacent quantum well layer; the upper layer being p-type doped and having a second contact electrically connected thereto; wherein an electroluminescence spectrum of emissions from the device is controlled in wavelength by passing a varying current through the device between said first and second contacts.