A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Part of the work leading to this invention was carried out with United States Government support provided under Contract No. DAAD19-00-2-0004 awarded by United States Army Research Office and Grant No DE-FC26-04NT42275 from the United States Department of Energy. Thus, the United States Government has certain rights in this invention.