Ultraviolet photodetector fabricated using laser sintering method grown Mg_0.2Zn_0.8O film

The Mg_0.2Zn_0.8O thin films were prepared on quartz substrate by laser sintering method. The effects of laser power density and irradiation time on the film structure and photoelectric properties were studied. Through XRD, SEM, and absorption spectrum test analysis, the optimal sintering technology parameters were determined. The laser power density and the laser irradiation time were determined as 53 W cm⁻² and 30 s. The optimal thin film was used to prepare the MSM structure UV detector. Current–Voltage (I–V) curves were obtained under dark and ultraviolet illumination conditions, and the curves show obvious Schottky contact behavior. Ideality factor, barrier height, and saturation current density were calculated as 1.38, 0.44 eV, and 1.21*10^–4 A cm⁻². The detector exhibits the low dark current (4 nA at 20 V), high photocurrent-to-dark current ratio of 10⁴. Correspondingly, the detectivity (D*) of 4.42 × 10¹² cm Hz^1/2 W⁻¹ (Jones) and linear dynamic range of ~ 64 dB are also achieved. Above results show that the device has a larger photocurrent-to-dark current ratio and a strong ability for characterizing the signal-to-noise ratio, which makes it has the detection capacity even in weak UV environments.