Post-annealing effects on Si-doped Ga2O3 photodetectors grown by pulsed laser deposition

Abstract

We studied Si-doped Ga2O3 photodetectors with a metal-semiconductor-metal structure that were fabricated using pulsed laser deposition and a post-annealing process under an oxygen atmosphere in a temperature range from 500 degrees C to 800 degrees C. After post-annealing, the Si-doped Ga2O3 photodetectors with 500 degrees C was showed the highest photoresponsivity (0.34 A/W) and external quantum efficiency (166.23%), while the device with 800 degrees C was exhibited the fastest switching speeds (0.88 s/0.18 s) for the on/off switching. These results are due to changes in the defect densities from the chemical bond formation between Si and O atoms. Our results show that post thermal annealing of Si-doped beta-Ga2O3 layers can modify the photo detector performance depending on applications for high photoresponsivity or fast response time.