Deposition Ga-doped ZnO films on PEN substrate at room temperature for thin film silicon solar cells

ZnO:Ga thin films were deposited by DC magnetron sputtering using two facing Ga-doped ZnO ceramic targets at room temperature. Polyethylene naphthalate (PEN) and Eagle2000 glass were used as substrates. The influence of PEN and glass substrates on the properties of ZnO:Ga thin films has been investigated. The distance between substrate and plasma dependence of micro-structure and electrical properties was also studied. The lowest resistivity obtained was 6.65 × 10−4 Ω cm with a Hall mobility of 17.1 cm2 V−1 s−1 and a carrier concentration of 5.5 × 1020 cm−3. When those ZnO:Ga thin films were applied to low-temperature flexible a-Si:H solar cells, an initial conversion efficiency of 5.91% was achieved.