Low-temperature deposition of Cu(InGa)Se2 solar cells on various substrates

Thin films of Cu(In,Ga)Se2 were deposited at substrate temperatures (Tss) of 550°C and 350°C on soda-lime glass/Mo and titanium foil/Mo. The effects of these parameters on the physico-chemical, optical and electrical properties of the films were studied as well as the influence of an alkaline source in the films. The control of the composition of the films using the end point detection method was also studied. Solar cells were then fabricated and the influences of the same parameters were analyzed. Efficiencies ranged from above 12% on both substrates at 550°C in the presence of Na to 10% on Ti without Na. Lower efficiencies were obtained at 350°C due in part to difficulty with the end point detection technique and in part to smaller grain sizes.