Growth of MnS Thin Film on c-Sapphire by Pulsed Laser Deposition

Abstract

Pulsed laser deposition was utilized to grow MnS thin films on c-sapphire substrate using a KrF excimer laser at growth temperatures that ranged from room temperature to <TEX>$700^{\circ}C$</TEX>. The results of X-ray diffraction (XRD) and UV-visible spectroscopy were employed to investigate the structural and optical properties of the MnS films. While the growth rate decreased as <TEX>$T_s$</TEX> increased, the overall quality of the film improved. The highest quality MnS film was obtained at <TEX>$700^{\circ}C$</TEX>. Variations in the <TEX>$T_s$</TEX> resulted in the MnS films exhibiting different growth mechanisms. The oriented (200) rocksalt MnS film was grown at room temperature. In the case of higher <TEX>$T_s,\;200{\sim}500^{\circ}C$</TEX>, the films consisted of mixed phases of rocksalt and wurtzite. The main structure of the films was altered to (111) rocksalt when the temperature was increased to in excess of <TEX>$600^{\circ}C$</TEX>. This behavior may very well be the result of elements such as surface energy and atomic arrangement during the growth process. The optical band gap of the obtained <TEX>${\alpha}-MnS$</TEX> film was estimated to be 3.32 eV.