Improvement of the UV-Sensing Performance of Ga-Doped ZnO Nanostructures via a Wet Chemical Solution at Room Temperature

In this investigation, ultraviolet (UV) photodetectors (PDs) were fabricated from zinc oxide (ZnO) and Ga-doped ZnO nanostructures on a Corning glass substrate by a simple wet chemical solution method at room temperature. The prepared devices contained two-dimensional (2-D) nanosheet (NS) structures, which could provide a large surface-area-to-volume ratio for UV-sensing. The ZnO and Ga-doped ZnO materials were respectively named ZPD and ZPD-G. All of the samples revealed a hexagonal wurtzite structure and grew preferentially along the (002) crystal plane. Compared with the photoluminescence (PL) spectrum of the ZPD NSs, the corresponding spectra of the ZPD-G NSs in the 380 nm region and green emission were clearly red-shifted and the number of oxygen vacancies slightly decreased. Under 380 nm UV illumination and a 3 V applied bias, the ZnO UV PDs doped with Ga elements exhibited much higher photoresponsivity and stability compared with the un-doped ZnO PDs, indicating good electrical performance. The ZPD-G samples possessed higher rise and recovery times compared with the ZPD samples; this finding could be attributed to the ability of the former to generate numerous electrons.