Research on ZAO transparent conducting films for flexible substrate Si based solar cells

In this paper, ZnO:Al (ZAO) films are deposited by using twin-target DC magnetron sputtering at room temperature, which are used as the window electrodes of flexible substrate a-Si:H solar cells. ZAO films structure, composition and photo-electronic properties are optimized by adjusting the Ar flow parameter from 1.67×10 -7 m 3/s to 8.33×10 -7 m 3/s. As the result of the experiment, the realized Ar flow is 3.33×10 -7 m 3/s, and the optimized ZAO films with high crystallization structure and c-axis orientation are obtained, the films' Hall resistivity is 4.26×10 -4 Ω·cm, the carrier concentration is 1.8×10 21 cm -3 and the visible region light transmittance is over 85%. Using the ZAO films on the window electrodes of flexible substrate a-Si:H solar cells, the conversion efficiency is extended to 4.26%.