We found that sputtered ZnO:Al films with an appropriate compact structure develop a surface texture during etching in diluted HCl with excellent optical and light trapping properties. Moreover, these texturable films have a high optical transmission and good electrical properties which are not affected by the etching process. An analysis of the film structure by HRSEM is presented. High short-circuit currents have been achieved for a-Si-H solar cells incorporating these films as TCO substrates.