Study on the Effect of Thermal Shock on Al‐Doped ZnO Films

Abstract

Al‐doped ZnO (AZO) films are fabricated on Si wafer and quartz glass by radio‐frequency (RF) magnetron sputtering. 2 × 2 × 2 AZO supercells are built and analyzed using first principles based on density functional theory. The thermal shock is performed on AZO with 10, 20, 30, 40, and 50 shocks according to photoelectric testing standards. After the thermal shock, X‐ray diffraction (XRD) shows that the (002) diffraction peaks are relatively stable, and the obvious (100) preferential orientation is observed under 10 shocks, Fourier transform infrared (FTIR) and XRD show the structures of AZO films have little change and maintain hexagonal wurtzite structure, X‐ray photoelectron spectroscopy (XPS) shows the Zn 2p binding energy all shift to the higher energy, indicating the high oxygen content in shocked AZO films. The simulation results show that the bandgaps decrease and the Fermi energy moves slightly to conduction band minimum after thermal shock. The experimental and simulation results indicate that the transmittance of AZO degrades significantly due to the increase in oxygen concentration, which means the thermal factor is adverse to photodetectors and solar cells related to light absorption and transmission.