Catalyst-free growth of GaN nanowires with molecular beam epitaxy produces material of exceptionally high quality with long minority carrier lifetimes and low surface recombination velocity. The nanowires grow by thermodynamic driving forces that enhance the sticking coefficient of incoming reagents to the end facets of the nanowire while preventing growth on the m-plane sidewalls. Photoluminescence (PL) studies confirm that the material is essentially free of detrimental chemical impurities and crystalline defects. The nanowires are readily excited to lasing with modest optical pump power. Recent progress in methods for selective epitaxy has made it possible to control both the diameter and placement of the nanowires. Despite the high material quality, the efficiency of single nanowire emitters remains low. The primary limitation appears to be optimizing the p-type doping with Mg, which is both a growth and a measurement problem.
Citation: Journal of Crystal Growth
Pub Type: Journals
GaN nanowires, molecular beam epitaxy, optoelectronics