Eur. Phys. J. Plus (2016) 131: 113
https://doi.org/10.1140/epjp/i2016-16113-8

Regular Article

Preparation and characterization of CuInS₂ absorber layers by sol-gel method for solar cell applications

¹ Department of Physics, Shahrood University of Technology, 36155-316, Shahrood, Iran
² Department of Chemistry, Shahrood University of Technology, 36155-316, Shahrood, Iran

^* e-mail: Amerioun@Shahroodut.ac.ir

Received: 12 April 2015
Revised: 10 January 2016
Accepted: 8 February 2016
Published online: 22 April 2016

Abstract

CuInSe₂ , CuInS₂ ( CIS₂ and CuInGaS₂ alloys and their compounds with band gaps between 1.05 and 1.7eV are absorbance materials based on chalcopyrite, in which, because of their suitable direct band gap, high absorbance coefficient and short carrier diffusion are used as absorbance layers in solar cells. In this work, the effects of decrease in p H and thickness variation on characteristics of the CIS₂ absorber layers, grown by spin coating on glass substrates, are investigated. Furthermore by using thiourea as a sulphur source in solvent, the sulfurization of layers was done easier than other sulfurization methods. Due to the difficulty in dissolving thiourea in the considered solvent that leads to a fast deposition during the dissolving process, precise conditions are employed in order to prepare the solution. In fact, this procedure can facilitate the sulfurization process of CuIn layers. The results obtained from this investigation indicate reductions in absorbance and band gap in the visible region of the spectrum as a result of decrease in p H. Finally, conductivity of layers is studied by the current vs. voltage curve that represents reduction of electrical resistance with decrease and increase in p H and thickness, respectively.