Comparison of fabrication, optical and photoresponse properties of Ga2O3 (310) and (2‾ 01) thin films on sapphire substrates

Monoclinic β-Ga 2 O 3 (310) and ( 2 ‾ 01) thin films were obtained on c -plane sapphire substrates by pulsed laser deposition (PLD) growth at 575 °C, as well as via a hybrid process involving PLD deposition at 750 °C followed by post-annealing, respectively. Compared with the β-Ga 2 O 3 ( 2 ‾ 01) thin film, the main advantages of the β-Ga 2 O 3 (310) thin film include high crystallinity, low root-mean-square (RMS) roughness, a narrower optical bandgap (4.6 eV), and weaker dispersion within a light wavelength range of 300-900 nm. In order to evaluate the suitability of the two films for optoelectronic applications, the photodetector devices were fabricated. In contrast, the β-Ga 2 O 3 (310)-based photodetector (PD) under 254 nm UV light presents many advantages such as fast response speed (τ r = 1.10 s), high responsivity (1.74 × 10 2 mA/W), and high external quantum efficiency (854%). This study lays a foundation for understanding the properties of β-Ga 2 O 3 (310) films and their applications in the field of photodetectors.