Ultrahigh performance of β-Ga₂O₃-based MSM solar-blind photodetectors fabricated via the glancing angle deposition technique

Glancing angle deposition (GLAD) is a simple, cost-effective, and mask-free method for fabricating microstructures by controlling the morphological structure. In this study, we investigated the effect of the deposition angle on the growth of nanorod structures on P–Si (100) and quartz substrates using the RF-sputtering method. The X-ray diffraction (XRD) patterns of samples fabricated at various deposition angles of 0°, 45°, and 65° reveal the monoclinic structure of β-Ga₂O₃. As the flux angle of the sputtered atoms increased, the intensity and width of the (−110), (−202), and (111) planes decreased, while the intensity of the (−111) plane increased. Moreover, the photoluminescence spectra of β-Ga₂O₃ nanocolumns showed five Gaussian bands with center wavelengths of 390, 434, 470, 494, and 525 nm, whose intensity is strongly affected by the deposition angle due to the increased path length of incident light. The characterization results of the fabricated metal–semiconductor–metal photodetector (MSM-PD) revealed the improvement of the optical properties of the sample deposited at a 65° oblique angle, which showed a responsivity of 95.28 A/W, a detectivity of 2.51 × 10¹³ Jones, a quantum efficiency of 4.8 × 10⁴ %, and a rise time of 44 ms for UVC light.