Highly (100)-orientated SnSe thin films deposited by pulsed-laser deposition

Abstract

This work aims at improving the quality of the highly (100)-orientated SnSe thin films for thermoelectric applications. The as-deposited films were obtained by controlling the basic parameters including target-to-substrate distance, deposition time and growth temperature through pulsed-laser deposition. The films quality was further improved by vacuum thermal annealing. The microstructure and crystalline structure of the films were studied by X-ray photoelectron spectroscopy, X-ray diffraction, electron probe micro-analyzer, electron back-scatter diffraction, atomic force microscope and Raman spectroscopy. The SnSe thin films grown on SiO2/Si substrate at 673 K followed by thermal annealing at 673 K for 30 min show the best crystal quality and uniform orientation with mirror-like surface, and the corresponding Seebeck coefficient and power factor are about 383 μV/K and 15.4 μW/m⋅K2, respectively. Angle resolved polarized Raman spectroscopy proved that the surface of the SnSe films is the b-c plane with preferred (100) orientation crystalline over a large area, providing an important way to prepare thermoelectric thin film devices by pulse laser deposition.