Critical issues for the growth of high-quality (Al,Ga)N/GaN and GaN/(In,Ga)N heterostructures on SiC(0001) by molecular-beam epitaxy

Abstract
We identify and discuss the essential strategies for the growth of (Al,Ga)N/GaN and GaN/(In,Ga)N heterostructures on SiC(0001) by both plasma-assisted and reactive molecular-beam epitaxy. Substrate preparation, nucleation, and growth conditions are optimized for simultaneously satisfying the requirements of high structural, morphological, optical, and electrical quality. The results demonstrate that molecular-beam epitaxy is a competitive technique for the growth of group-III nitrides.