Effects of annealing temperature on properties of gallium oxide thin films and ultraviolet detectors br

In this work, gallium oxide (Ga2O3) thin films are deposited on quartz substrates by radio frequencymagnetron sputtering at room temperature and annealed in argon atmosphere at different temperatures. Theinfluences of annealing temperatures in the argon atmosphere on crystal structure, transmittance, surfacemorphology, and optical band gap of the samples are investigated in detail. It is found that the annealingprocess can improve the crystalline quality of the film, but high-temperature annealing can also easily causeoxygen elements in the film to escape from the film to form oxygen vacancies, which is evidenced by XPS testresults. To obtain the effect of the annealing process on the performance of gallium oxide thin film detector, themetal-semiconductor-metal (MSM) photodetector based on the sample annealed at 800 degrees C, which is comparedwith untreated sample operated at a reverse bias voltage of 1.1 V, can achieve excellent comprehensive photo-detection properties for 254 nm ultraviolet light: the light-dark current ratio (I254/Idark), responsivity andspecific detectivity are as high as 1021.3, 0.106 A/W and 1.61 x 1012 Jones, respectively, which are 7.5, 195 and38.3 times those of the unannealed sample device. And the external quantum efficiency is improved by 51.6%.The rise time of sample detector (0.19/0.48 s) annealed at 800 degrees C decreases compared with that of theunannealed sample (0.93/0.93 s), and the descent time of 800 degrees C detector (0.64/0.72 s)increases compared withthat of the unannealed sample (0.45/0.49 s), respectively. By comparing the parameters with those of othercurrent gallium oxide-based MSM photodetectors, it is found that the detector parameters of this work havesome gaps compared with the current optimal parameters, which is attributed to the fact that the quartzsubstrate is selected for this work and not the sapphire substrate that is better matching with gallium oxide,resulting in the poor quality of the film compared with that of the sample on the sapphire substrate, and in thiswork, the photodetector has the high light-dark current ratio (PDCR) and detection rate (D*). In the end, themechanism of increasing oxygen vacancies after being annealed, which leads to the improvement of detector performance parameters, is analyzed in detail

Automated summary

Gallium oxide (Ga2O3) thin films were deposited on quartz substrates using radio frequency magnetron sputtering and annealed in argon atmosphere at different temperatures. The annealing process improved the crystal quality but also caused oxygen vacancies. The photodetector based on the annealed sample showed significantly improved performance compared to the unannealed sample.