Production and Characterization of Cu2SnS3 Absorber Layers for Photovoltaic Solar Cell Applications

Abstract

Next-generation thin film solar cell technologies require the use of abundant photovoltaic absorber materials in nature. Various materials such as CuInGaS (CIGS), CIGSSe CdTe, and Cu2ZnSnS4 (CZTS) have been explored and used for solar cell technology. Nevertheless, the complex crystal structure and the elemental toxicity restrict them for photovoltaic applications. Studies in recent years have begun to reduce costs and complexity in the structure of new ternary semiconductors [1]. Among them, Cu2SnS3(CTS) is an earth abundant, non-toxic material with direct band gap energies of 0.93-1.77 eV. Suitable electrical and optical properties they exhibit, promise their use as absorbent layer for photovoltaic applications [2]. Unfortunately, the material still needs to improve for high efficiency [3]. Depending on the deposition technique, several secondary phases may appear and affecting the formation reactions during the sulfurization process of the film [4]. Insufficient conversion of binary sulfides during thermal process may lead to the formation of unwanted compounds which affect the crystallization of CTS. In this work, Cu-Sn precursor metals deposited on glass substrates by Physical Vapour Deposition (PVD) technique. In the second stage, the production of CTS films was completed by applying a sulfurization process in a furnace at different sulfurization temperatures. Many physical features have been examined such as optical, structural, surface and electrical properties of the films and were investigated in detailed with the help of Xray diffraction, Raman spectroscopy, UV-VIS Spectroscopy, atomic force microscopy, scanning electron microscopy and four-point probe techniques.