Ultrasensitive p-n junction UV-C photodetector based on p-Si/β-Ga2O3 nanowire arrays

Abstract

Ultrasensitive UV-C photodetector (PD) based on β-Ga2O3 nanowires (NWs) were fabricated on p-type Si substrate using glancing angle deposition technique inside RF/DC sputtering chamber. The formation of well-aligned NWs with an average length of ~ 270 nm was confirmed with the help of field emission scanning electron microscope (FE-SEM) images. Also, the fabricated β-Ga2O3 NWs array were polycrystalline in nature. Furthermore, a good photo absorption and photoemission were obtained from the fabricated sample. The PD fabricated using β-Ga2O3 NW operated in the UV-C region (275 nm) with a recorded responsivity of 31.71 A/W, detectivity of 1.37×1012 Jones and an NEP of 2.44×10−12 W at + 5 V. Additionally, the PD was able to respond at a very low power light of 6.37 µW/cm2. The transient response of the fabricated device shows a rise time and fall time of 0.18 s and 0.25 s respectively. The high performance was attributed to the strong p-n junction which could separate the photogenerated carriers efficiently.