Influence of growth temperature of transparent conducting oxide layer on Cu(In,Ga)Se2 thin-film solar cells

We have studied the influence of growth temperature (TG) in the deposition of an indium tin oxide (ITO) transparent conducting oxide layer on Cu(In,Ga)Se2 (CIGS) thin-film solar cells. The ITO films were deposited on i-ZnO/glass and i-ZnO/CdS/CIGS/Mo/glass substrates using radio-frequency magnetron sputtering at various TG up to 350 °C. Both the resistivity of ITO and the interface quality of CdS/CIGS strongly depend on TG. For a TG ≤ 200 °C, a reduction in the series resistance enhanced the solar cell performance, while the p–n interface of the device was found to become deteriorated severely at TG > 200 °C. CIGS solar cells with ITO deposited at TG = 200 °C showed the best performance in terms of efficiency.