Structural and Optical Characterization of High-Quality Cubic GaN Epilayers Grown on GaAs and 3C-SiC Substrates by Gas-Source MBE Using RHEED In Situ Monitoring

By monitoring RHEED reconstruction patterns during gas source molecular beam epitaxy growth, the optimization of the growth for cubic GaN was carried out successfully. Cubic GaN epilayer having a X-ray diffraction width of 16min and a low temperature photoluminescence emission width of 19meV was obtained on a 3C-SiC substrate by adjusting the effective III/V ratio in-situ during the growth, which can be inferred from the surface reconstruction transitions. It was found that the surface reconstructions of cubic GaN surfaces are good indices for the optimization of growth parameters.