Patent ID: 8461568

Claim:
A device, comprising: a stack of semiconductor layers, the stack including: an active region adapted to convert light at a first wavelength λ 1 to light at a second wavelength λ 2 , the active region including at least a first potential well; and a first inactive region extending from an outer surface of the stack to the active region, a distance from the outer surface to the active region corresponding to a thickness of the first inactive region, the first inactive region characterized in that light at the first wavelength λ 1 propagating therein is not substantially converted to other light; wherein the stack also includes a plurality of depressions formed therein that extend from the outer surface into the first inactive region, the depressions being characterized by an average depression depth, and wherein the average depression depth is at least 50% of the thickness of the first inactive region, wherein the active region of the semiconductor layer stack also includes a first absorbing layer closely adjacent to, and having a band gap energy greater than a transition energy of the first potential well.