Growth of GaN on nano-crystalline diamond substrates

In this study GaN has been grown on nano-crystalline diamond substrates utilizing metal-organic chemical vapour deposition (MOCVD). It is shown that the growth of closed GaN films onto synthetic diamond substrates is feasible, when applying the correct buffer layer and growth parameters. XRD measurements showed that the GaN formed is of wurzite structure and polycrystalline, but the high intensity of the (0002) diffraction peak indicates a preferential crystallite orientation. This preferred [0001] orientation was confirmed by SEM analysis. The optical quality of the deposited GaN layer was investigated using cathodoluminescence and showed a large yellow luminescence peak. This work comprises a first step in preparing heterogeneous layers and GaN devices with a diamond heat sink as a substrate, facilitating the thermal management of these devices.