Ag/Ga₂O₃/n-Si Schottky-type photodetector for visible light detection

Gallium oxide (Ga2O3) is an ultra-wide band gap material which has been receiving increasing interest for its potential applications in power electronics, ultraviolet (UV) photodetectors, and gas sensors. In this study, we have synthesized beta-phase Ga2O3 on n-Si substrate using the electrodeposition technique, and investigated its properties for use in photodetector applications for broadband detection combining Si and Ga2O3. X-ray diffractometer (XRD), scanning electron microscope (SEM) with energy dispersive x-ray (EDX) analysis were conducted to illuminate structural and morphological behaviors of the Ga2O3. Ag metallic contacts on the Ga2O3/n-Si junction and Al ohmic contact on the back surface of the n-Si were obtained by thermal evaporation technique. Thus, Ag/Ga2O3/n-Si Schottky-type photodetectors were fabricated and characterized by current-voltage (I-V) measurements depending on various light power intensities and wavelengths ranging from UV to near-infrared (NIR). The diode characteristics, as well as the photodetection parameters such as responsivity, specific detectivity, and external quantum efficiency (EQE) were determined and discussed in detail. The Ag/Ga2O3/n-Si Schottky-type photodetectors showed high performances: 122.88 A/W responsivity, 1.07 x 1012 Jones specific detectivity, and very high EQE value of 2.18 x 104% at 700 nm wavelength. The obtained Ag/Ga2O3/n-Si Schottky-type photodetector exhibits promising potential as a candidate for optoelectronic applications in the visible range. These photodetectors can be used in visible light communication, light sensing and cameras.