Efficient temperature sensor based on green emissions from Er-doped β-Ga2O3 thin film

The optical temperature sensing properties based on the β-Ga2O3:Er film were reported. Using a laser with 488 nm as an excitation source, the temperature-dependent behavior of the fluorescence intensity ratio of two green emissions at 524 nm and 550 nm corresponding to the thermal coupled energy levels of 2H11/2 and 4S3/2 was investigated in the temperature range of 77 K–400 K. The maximum absolute and relative sensitivities were found to be 0.003 K−1 at 400 K and 1031/T2. In comparison with the temperature sensor based on GaN:Er/Yb, the temperature sensor based on β-Ga2O3:Er without any sensitizer in this work can operate at higher temperatures. The thermal effect induced by the radiation of laser was also investigated, and the results show that the thermal effect induced by the pump power in this work can be negligible. These results suggest that the β-Ga2O3:Er film is a potential material for application in optical temperature sensing.