Enhanced Photoresponse in MIS-Type UV-Vis Photodetector via Biocompatible Glutathione(C10H17N3O6S) Interlayer: Theoretical and Experimental Analysis

Abstract

Commercially available glutathione (GSH) compound isspin coated on n-Si wafer to passivate the surface of Si. The optical absorption and SEM analysis of the GSH film are performed. The optical bandgap energy of the GSH and the fundamental bandgap energy are equal to 5.526 eV and 6.325 eV, respectively. GSH presents much lower value of binding energy. It isobserved that the Au/GSH/n-Si MIS junction exhibited both a dark-rectifying ratio of 3370 and an excellent photoresponse in the visible light, UV and IR regions. Comparing the Au/GSH/n-Si junction with the Au/n-Si diode, the reverse current of the device containing the GSH interlayer decreased by more than 3 orders of magnitude. Since the low reverse current is essential for high performance in photodetectors, the photoresponse analysis of the device isinvestigated in detail. The highest responsivity and detectivity values under 365 nm UV light are 53.18 mA/W and 2.18 x 1011 Jones, respectively. Time-dependent I-V characteristics showed that the MIS device photosensitive device maintained its stability even after 110 days. These experimental results show that the Au/GSH/n-Si MIS photodetector has the potential for optical signal communication in a wide wavelength region.