Growth of InN on Ge(1 1 1) by molecular beam epitaxy using a GaN buffer

Abstract

Many novel applications are foreseen for the InN-containing materials especially when cheap, conductive substrates can be used. In this paper, we report on the growth of pure InN layers on germanium (Ge) (1 1 1) substrates. We found that high-quality InN can be grown on Ge(1 1 1) with plasma-assisted molecular beam epitaxy when using a thin GaN intermediate layer. On such intermediate GaN layers, 50 nm InN layers were grown and analyzed by RHEED, XRD, AFM, Hall and I– V measurements. Additionally, using ellipsometry we could determine that the optical bandgap of these InN layers lies around 0.85 eV. Our results indicate that Ge(1 1 1) is a promising substrate for vertical conducting devices, with In(Ga)N on top.