IMPACT OF SELENIZATION TEMPERATURE AND PRE-ANNEALING TREATMENT ON THE MICROSTRUCTURAL PROPERTIES OF Cu2ZnSnSe4 THIN FILMS GROWN BY RAPID THERMAL PROCESS

The impact of selenization temperature and pre-annealing treatment on the microstructural characteristics of CZTSe thin films were studied. CZTSe thin films were obtained by two-stage process. This processes includes deposition of metallic layers and Se cap layer employing physical vapor deposition systems followed by selenization process performed at elevated temperatures using RTP system with a heating rate of 8°C/s. The compositional properties of CZTSe thin films changed after the heat treatment, but performing pre-annealing treatment before high reaction temperature (550°C) partially prevented element loss in CZTSe compound. Both Raman and XRD measurements confirmed the formation of the kesterite CZTSe phase. However, according to Raman results, CZTSe phase started to decompose into secondary phases such as CTS regardless of temperature. According to the top view images of the samples, the grain structure completely changed with employing heat treatment. Zn-rich phase detected in reacted sample at 550 °C, which indicates decomposition of CZTSe that is confirmed in Raman spectra.