Modification Of Ingan Quantum Well Luminescence By Microstructured Buffer Layers

With the aim of increasing the efficiency of green and blue light-emitting diodes, we investigate the luminescence of InGaN/GaN quantum wells on structured GaN buffer layers.The peak emission wavelength of such systems depends among other factors on the In concentration, but the latter cannot be increased at will during growth of the quantum well structures, for stability reasons. However, it depends in turn on the buffer surface orientation, and therefore structuring the buffer before growth of the quantum wells can result in local variations of In concentration, and consequently peak emission wavelength.We present first results of local modification of emission wavelength, as shown by photo- and cathodoluminescence, and propose further experiments.