Low temperature sulfurization of electrodeposited Cu(In,Al)Se2 thin films

Sulfurization of Cu(In,Al)Se2 films is carried out in an indigenously made set up at moderately low temperature. The films are sulfurized for different time durations of 15, 30, 45 and 60 min at 150 °C. InSe and Cu2S phases occurred in the films during the initial stage of sulfurization along with Cu(In,Al)(Se,S)2 phase. The compositional analysis shows that the sulfur incorporation is saturated after 30 min. Crystallinity increased with the increase in sulfurization time. The band gap of the Cu(In,Al)Se2 film increased up to 1.35 eV with the addition of sulfur. Single phase Cu(In,Al)(Se,S)2 with high crystallinity is obtained after 60 min of sulfurization.