The Effect of Substrate Temperature on the Microstructure and Thermoelectric Properties of Pulsed Laser Deposited Cu2SnSe3 Thin Film

Cu2SnSe3 is a potential candidate for a variety of applications which include thermoelectric, optoelectronic and solar energy. Many studies were carried out to investigate the thermoelectric properties of polycrystalline Cu2SnSe3 materials, but studies on thermoelectric properties of thin film Cu2SnSe3 have not been reported so far. Thin Cu2SnSe3 films were successfully deposited through pulsed laser deposition on silicon substrate under Ar pressure of 5 mTorr at substrate temperatures of 300, 350 and 400 degrees C. The crystalline phases of the thin film samples were studied by X-ray diffraction, which revealed the formation of Cu2SnSe3 monoclinic phase in all three samples. The obtained films were polycrystalline, have uniform thickness and coarse particle agglomerates on the surface. Atomic force microscopy analysis was performed to study the samples morphology and surface roughness. The as-deposited films were p-type with positive values of Seebeck coefficient, which was confirmed by the thermoelectric probe measurements. The sample deposited at 350 degrees C has the highest power factor of about 2.8*10(-4) (W/m(2)K), among the studied samples. The high power factor along with other benefits like higher energy density, light weight and compact size makes Cu2SnSe3 thin film potential candidate for various energy applications.