Tunable van der Waals Doping in WS₂/CrOCl Heterostructure by Interlayer Coupling Engineering

Abstract

In contrast with substitutional doping, van der Waals doping is essential in two-dimensional (2D) semiconductors to avoid carrier scattering. Here, we take the WS2/CrOCl heterostructure (HS) as an example to investigate tunable van der Waals doping by uniaxial strain engineering. Because of different work functions, electrons transfer to CrOCl from WS2, leading to electrostatic doping of WS2 and a built-in electric field from WS2 to CrOCl. Photoexcited electrons also transfer from WS2 to CrOCl but are hindered by the built-in electric field, saturating the doping in WS2. Moreover, uniaxial strain can continuously modulate the interlayer coupling of WS2/CrOCl HS, leading not only to electrostatic doping but also to photoinduced doping in WS2. These results demonstrate that uniaxial strain is an effective strategy to tailor van der Waals doping in 2D semiconductors for applications in 2D electronics and optoelectronics.