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

Incontrast with substitutional doping, van der Waals doping isessential in two-dimensional (2D) semiconductors to avoid carrierscattering. Here, we take the WS2/CrOCl heterostructure(HS) as an example to investigate tunable van der Waals doping byuniaxial strain engineering. Because of different work functions,electrons transfer to CrOCl from WS2, leading to electrostaticdoping 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 straincan continuously modulate the interlayer coupling of WS2/CrOCl HS, leading not only to electrostatic doping but also to photoinduceddoping in WS2. These results demonstrate that uniaxialstrain is an effective strategy to tailor van der Waals doping in2D semiconductors for applications in 2D electronics and optoelectronics.