Near-Infrared light detection properties of n-WS₂/AlN/p-Si SIS heterostructures

In this study, n-WS₂/AlN/p-Si semiconductor-insulator-semiconductor (SIS) heterostructures were fabricated using the RF magnetron sputtering technique with varying WS₂ deposition times. The structural and morphological properties of the produced heterostructures were characterized using XRD, SEM, and AFM measurements. While the formation of the WS2 phase with a hexagonal structure was confirmed by XRD results, it was determined from SEM and AFM analyses that the crystallinity improved but the surface roughness increased with increasing the thickness of the WS2 thin film. The optical properties of the heterostructures were further examined by UV–Vis–NIR spectroscopy and photoluminescence (PL) measurements, providing insight into thickness-dependent absorption behavior and defect-related optical transitions. Furthermore, the effect of the WS₂ layer thickness on the photoresponse characteristics of the fabricated heterostructure was systematically investigated. Considering the photoresponsiveness characteristics investigated with current-voltage measurements in the dark and under 780 nm illumination, the device, fabricated with a WS₂ thin layer of approximately 10 nm thickness, demonstrates high performance with a photoresponsiveness of 1.058 A/W at low voltage. These findings show that WS₂/AlN/Si SIS heterojunctions, which possess an excellent carrier transport mechanism, indicate strong potential for next-generation high-performance optoelectronic applications.