Effect of n-type Cl doping on electrical conductivity of few layer WS2

Abstract

The work reported here focuses on improving the electrical conductivity of tungsten disulfide (WS₂) nanosheets by n-type impurity doping. The WS₂ is a 2D transition metal dichalcogenide material which possess desirable properties such as high mobility and bandgaps, making them potential candidates for future semiconductor device applications. However, the presence of sulfur vacancies in semiconductor and weak binding energy at the metal–semiconductor interface often results in a high Schottky barrier height (SBH) leading to poor electrical conductivity. To overcome this issue, the research focusses on investigating the reduction of SBH at the junction between WS₂ and metal. The effect of time dependent chlorine (Cl) doping on the SBH of exfoliated WS₂ was studied through I–V measurement at different temperatures. The results indicate SBH reduction from 0.75 eV for undoped to 0.65 eV for Cl doped samples. Overall, the study demonstrates that Cl doping can effectively decrease the Schottky barrier height of WS₂ thin-film, leading to enhanced electrical transport properties. The mechanism involved in the modulation of electronic property of the system is also explained with the help of an energy band model. These findings contribute to the understanding and advancement of high-performance semiconductor devices established on the n-type doping of WS₂ thin film.