The Comparison of (Ag,Cu)(In,Ga)Se$_{\bf 2}$ and Cu(In,Ga)Se$_{\bf 2}$ Thin Films Deposited by Three-Stage Coevaporation

Abstract

(Ag,Cu)(In,Ga)Se2 and Cu(In,Ga)Se2 thin-films with bandgap ~1.35 eV were deposited by a three-stage elemental coevaporation process. The depositions were conducted at substrate temperatures of 580 °C and 650 °C to understand the effects of Ag alloying and high growth temperature on material properties. Ag/(Ag+Cu) and Ga/(In+Ga) gradients were observed and were reduced with higher growth temperature. Grain size was quantified and found to be enhanced by Ag and high growth temperature, while film texture showed no significant change with different deposition conditions.