Fabrication and characterization of WS2/AlN/Si S-I-S heterojunction for emergent material photovoltaic applications

Abstract

Here, the WS₂/AlN/Si semiconductor-insulator-semiconductor (SIS) heterojunction based inorganic tungsten disulfide chalcogenide compound with the insertion of 10 nm thick Aluminium nitride (AlN) layer as insulator is investigated. Our study focuses on structural, surface morphology, optical and electrical properties of S-I-S heterojunction, fabricated by RF sputtering process, as a result of both WS₂ (10, 50 and 100 nm) thickness and light conditons change at room temperature (RT). The grain size determined by X-ray is smaller around 42 nm which confirms the nanostructural aspect. This aspect is also revealed by AFM and SEM observations. The transmittance (T) of three samples declines from 90.8 to 59.3% when WS₂ thickness rises. İt is observed that T-λ curves augment from UV range to Vis to highest point in IR band. The current versus voltage (I-V) characteristics of S-I-S are investigated in dark, solar simulator and filter 780 nm conditions. Related parameters are extracted from I-V curves showing an increase in both ideality factor and saturation current with WS₂ layer thickness.