A symmetrical quantum well active layer provides enhanced internal quantum efficiency. The quantum well active layer includes an inner (central) layer and a pair of outer layers sandwiching the inner layer. The inner and outer layers have different thicknesses and bandgap characteristics. The outer layers are relatively thick and include a relatively low bandgap material, such as InGaN. The inner layer has a relatively lower bandgap material and is sufficiently thin to act as a quantum well delta layer, e.g., comprising approximately 6 .ANG. or less of InN. Such a quantum well structure advantageously extends the emission wavelength into the yellow/red spectral regime, and enhances spontaneous emission. The multi-layer quantum well active layer is sandwiched by barrier layers of high bandgap materials, such as GaN.
STATEMENT OF GOVERNMENT INTEREST
 This invention was made with government support under U.S. National Science Foundation--ECCS Award #0701421, and US Department of Energy--NETL (DE-FC26-08NT01581). The government has certain rights in the invention.