Enhanced Photoresponse of Ultraviolet Photodetector via RF Sputtered ZnO/a-SiC Heterostructure

In this study, metal-semiconductor-metal (MSM) ultraviolet (UV) photodetector (PD) structure based on amorphous-silicon Carbide (a-SiC) was developed by RF sputtering deposition.
$\text{ZnO}$
thin-film behaving like as passivation and efficient UV absorber layer was sputtered on the a-SiC film forming a heterostructured device. A comprehensive study of the device structural and optical performances is performed by XRD and UV-Vis spectra measurements. Significantly, the fabricated device exhibits an excellent ultraviolet absorption ability (85%). Moreover, the elaborated MSM UV-PD reveals a good responsivity of 37
$\text{mA}/\mathrm{W}$
, an extremely reduced dark current of 10
$\text{pA}$
and high
$\mathrm{I}_{\mathrm{o}\mathrm{N}}/\mathrm{I}_{\mathrm{o}\mathrm{F}\mathrm{E}}$
ratio of 120
$\text{dB}$
at self-powered mode. These improved performances can be explained by the effect of the heterostructure nature of the developed ZnO/a-SiC, which leads to enhance photo-induced carrier generation mechanism and also transport of carriers. The obtained results suggest that the fabricated amorphous UV MSM PD herein show a cost-effective approach for developing novel self-powered UV photosensors potentially appropriate for high temperature and power applications.