Light induced phase change in Cu<inf>2-x</inf>Zn<inf>1.3</inf>SnS <inf>4</inf> thin films

Cu2ZnSnS4 and its alloy based thin film solar cells have shown better photovoltaic performance under Cu-poor and Zn-rich conditions. However, the effect of Cu-stoichiometry on the coexistence of kesterite (KS), stannite and/or partially disordered kesterite (PD-KS) phases and their influence on photovoltaic performance is not clearly understood. Raman studies were carried out on Cu2-xZn1.3SnS4 (x=0, 0.3, and 0.5) thin films by changing the intensity of the incident laser beam. It was observed that both Cu-stoichiometry and incident laser beam intensity induce a disorder in the system. Disorder induced transformation of KS I4 + to PD-KS 42m+ is explained by Raman studies. © 2014 AIP Publishing LLC.