MOCVD growth of InN using a GaN buffer

We have investigated MOCVD growth of InN on sapphire with and without a GaN buffer between 490 and 520 ∘C. The buffer significantly improves the surface morphological uniformity and electrical properties of InN epilayers. Characterization of the as-grown epilayers with the buffer reveals that kinetics-limited islands are formed at lower temperatures, whereas islands with equilibrium shape are obtained at higher temperatures. Below 520 ∘C, increasing temperature improves structural quality but degrades electrical properties. Hall data from this study suggest that VN-related defects/impurities are the possible donor species and compensation varies with charged dislocation acceptors. We believe that reducing carrier concentration and dislocation density is effective to increase the Hall mobility of InN.