Investigation on structural and opto-electronic properties of substitutional Sn doped WS2 by co-sputtering technique

The doping of two-dimensional materials provides them with tunable physical properties and broadens their application. In this study, the doping of tungsten disulfide with metallic Sn atoms via a co-sputtering technique was demonstrated. In particular, WS2 was deposited by radio frequency (RF) magnetron sputtering, while Sn atoms deposited by DC sputtering become substitutional dopants. It was revealed that the metallic tungsten atom, and in some cases sulfur vacancies, in the WS2 atomic layer created by RF magnetron sputtering were partially filled/substituted by metallic Sn atoms. The Sn-doped WS2 layers exhibited n-type doping behavior with remarkable opto-electronic properties (bandgap 2.09 eV, mobility 7.84 cm2/V·s and resistivity 2.81 × 103 Ω-cm for 1 min Sn doping) suitable for photovoltaic applications. Overall, this technique facilitates better control of the dopant distribution than the traditional approach.