Temperature optimization for MOCVD-based growth of ZnO thin films

Abstract

Several samples of Zinc Oxide thin films were grown using a homemade metalorganic chemical vapor deposition apparatus and tested using in-situ interferometry, photoluminescence spectrometry, ex-situ spectral reflectance, and ex-situ transmittance measurements. We found that despite having a relatively high thickness, samples grown in higher temperatures were of better crystal quality with higher exciton emission peaks, increased transmittance, and lower photoluminescence linewidth. However, kinetic energy from higher temperature growth led to increased defect-associated emission. We thus propose a model for temperature optimization in ZnO thin film growth by MOCVD wherein thermal rectification of thickness-associated defects and thermal induction of kinetic energy-induced defects must be balanced for improvements in crystal quality around the growth temperature of 550°C.