Comparative study of thermal stability of aluminium- and gallium-doped ZnO thin films prepared by sol–gel method

Abstract

To study the thermal stability of Al- and Ga-doped ZnO (AZO and GZO) films, these films with a doping concentration from 0·5 to 3 at-% have been prepared by sol–gel method on glass substrate followed by annealing in air. It has been found out that the AZO and GZO films have similar thermal stability, and Ga dopant cannot improve the stability. Moreover, the doping concentration has no prominent effect on the thermal stability. The resistivity of the films is stable when the annealing temperature is lower than 250°C and increases rapidly after that, while the transmittance increases with annealing temperature. The variations of the resistivity and the transmittance are closely related to the microstructure, and vacancy and electron concentration affected by the annealing treatment.