ATOMIC LAYER DEPOSITION OF ZnInXSY BUFFER LAYERS FOR COPPER INDIUM GALLIUM DISELENIDE THIN FILM SOLAR CELLS

摘要

We report in this paper the study of ZnIn_XS_Y films deposited by atomic layer deposition at 200 °Cfor buffer layers in CIGS solar cells. The growth was monitored at the atomic layer level by in situ quartz crystalmicrobalance technique. Buffer layers with different In/(In+Zn) ratios over the whole composition range wereprepared and characterized. Cell results show that an intermediate composition allows to find a compromisebetween the properties of In_2S_3 and ZnS as aimed for this study. Best efficiencies were obtained with indium richbuffer layers but with limited V_(oc) and light losses due to absorption in the short wavelengths. At the opposite,zinc rich buffer layers are more transparent and may allow higher V_(oc) and Jsc but increase interfacerecombination. In particular, the layer with In/(In+Zn) = 28 % led to a V_(oc) 30 mV higher than using a referenceCdS buffer layer and an equivalent Jsc but a decreased fill factor.