Phase composition of Cu2SnS3 thin films prepared by Ultrasonic Spray Pyrolysis as potential photovoltaic material

Abstract

Quaternary and ternary semiconductors derived from the Cu-Zn-Sn-S system, holds promise as absorber materials for thin film solar cells. This paper presents a study on the phase composition of Cu2SnS3 (CTS) thin films prepared by ultrasonic spray pyrolysis of CuCl2-2H2O, SnCl2 and thiourea (NH2)2CS water-ethanol mixtures. After being deposited on glass-slide substrates, the films were thermally treated at 380 °C for 50 minutes in vacuum. The as-deposited and annealed films consisted of a mixture of monoclinic and tetragonal CTS as determined by Raman spectroscopy. The prepared CTS films have p-type conductivity as verified by the hot-probe method, and energy gaps of 0.87 and 1.15 eV associated to monoclinic and tetragonal phases of CTS.