Effect of an AlN buffer layer on the epitaxial growth of InN by molecular-beam epitaxy

The effect of an AlN buffer layer on the epitaxial growth of InN by molecul ar-beam epitaxy (MBE) is studied. Using an AlN buffer layer can significant ly improve the structural and electrical properties of InN. With increasing thickness of the AlN buffer layer, the Hall mobility of InN will monotonic ally increase while the electron carrier concentration decreases. The surfa ce morphology of the film also improves. A Hall mobility of more than 800 c m(2)/V s with a carrier concentration of 2-3 x 10(18) cm(-3) at room temper ature can be routinely obtained on similar to0.1 mum InN film. More importa ntly, it is found that under optimum growth conditions, by using an AlN buf fer layer, InN films with comparable quality can be achieved by the convent ional MBE technique compared to InN grown by migration-enhanced epitaxy. In creasing InN thickness also increases Hall mobility. (C) 2001 American Inst itute of Physics.