The GaN Epilayer Grown by MOVPE: Effect of The Different Nucleation Layer Temperatures

Effect of different nucleation layer temperatures (LT-GaN growth temperature) on the properties of the subsequent GaN epilayer grown by MOVPE is investigated. In-situ reflectance curves demonstrate that higher LT-GaN growth temperatures cause fast coalescence (shorter transition time) of GaN nucleation islands. Both photoluminescence (PL) and high-resolution x-ray diffraction (HRXRD) are used to demonstrate the influence of LT-GaN growth temperature on optical and structural properties of subsequent GaN epilayer, respectively. It is observed that the change of LT-GaN growth temperature has an effect on both full-width at half-maximum (FWHM) values obtained from the results of HRXRD measurement and yellow luminescence peak intensity. It is seen that the yellow luminescence peak intensities for samples alter with LT-GaN growth temperature.