Examination of stimulated emission at ZnO thin films deposited by SILAR and spin coating methods

In this study, Zinc Oxide (ZnO) semiconductor layers were deposited on silicon substrates by using SILAR and spin coating methods. p-type and n-type silicon wafers were used as the substrates. The advantages and disadvantages of the two deposition methods were investigated by analyzing obtained samples. In order to observe the surface morphologies and crystal structures of the samples, scanning electron microscopy and X-ray diffraction measurements were taken and photoluminescence (PL) measurements were used to investigate the optical properties of the samples. The results of the SEM measurements showed that the surfaces were homogeneous and ZnO nano-rods were formed on the sample surfaces. The peaks belong to ZnO were observed from the XRD measurement results. The emissions around 380 nm wavelength were observed from PL measurements. When all obtained results were considered, it was realized that the spin coating method was more advantageous than the SILAR method. Besides, two-dimensional ZnO thin film structure was modelled and simulated by using finite-difference time-domain method. The simulation results for different pumping levels were obtained. The emission characteristics above and below the simulated emission threshold were investigated.