Effects of annealing temperature on microstructure, optical, and optoelectronic properties of Ga2O3:F-Nb films

This study successfully prepared Ga2O3:F-Nb films using the dual-target radio frequency co-sputtering technique and systematically investigated the effects of annealing temperature on the microstructure, optical, and optoelectronic properties of the Ga2O3:F-Nb films. The optimal annealing temperature for the Ga2O3:F-Nb films was found to be 400 degrees C, at which their MSM devices exhibited better performance. Additionally, when the annealing temperature was >= 600 degrees C, substrate mismatch and significant F loss led to film cracking or degraded device performance. Introducing a Ga2O3 transition layer partially addressed the substrate mismatch issue and restored the photoelectric response of the device. As the annealing temperature increased, the films' optical band gap widened and their crystalline quality improved. This enhancement in crystallinity was attributed to the reduction of oxygen vacancies during annealing. This study provides data and new insights for the research of multi- element doped Ga2O3 materials.