Metal-Semiconductor Nanoheterostructures with an AlGaN Quantum Well and In Situ Formed Surface Al Nanoislands

We report on fabrication and studies of composite heterostuctures consisting of an Al0.55Ga0.45N/Al0.8Ga0.2N quantum well and surface Al nanoislands, grown by plasma-assisted molecularbeam epitaxy on c-sapphire substrates. The influence of a substrate temperature varied between 320 and 700oC on the size and density of the deposited Al nanoislands is evaluated. The effect of Al nanoislands on decay kinetics of the quantum well middle-ultraviolet photoluminescence has been investigated by time resolved photoluminescence. The samples with the maximum density of Al nanoislands of 108 cm–2 and lateral dimensions in the range of 100–500 nm demonstrated shortening of the photoluminescence lifetime, induced by interaction of the emitting quantum well and the plasmonic metal particles.