Optimization of the process for sol-gel derived ZnO:Al thin films for transparent conducting oxide applications

Abstract

Transparent and conducting Al-doped ZnO thin films with c-axis-preferred orientation were prepared on glass substrate via sol-gel route. The physical, optical and electrical properties were investigated to determine an optimal withdrawal speed, aluminum source and treatment in order to obtain a smooth, dense, highly crystalline, conductive and transparent thin film with a high figure of merit for transparent conducting oxide applications. An optimal withdrawal speed was found to be 2.5 cm/min. Optimal aluminum source and concentration was found to be 0.5 at.% using aluminum chloride hexahydrate. An additional treatment in an N2 environment was found to be the best method to improve the electrical properties of the films while maintaining high crystallinity and transparency.