Dual-channel type tunable field-effect transistors based on vertical bilayer WS2(1−x)Se2x/SnS2 heterostructures

Layered semiconductor heterostructures are essential elements in modern electronic and optoelectronic devices.Dynamically engineering the composition of these heterostructures may enable the flexible design of the properties of heterostructure-based electronics and optoelectronics as well as their optimization.Here,we report for the first time a two-step chemical vapor deposition approach for a series of WS2(1−x)Se2x/SnS2 vertical heterostructures with high-quality and large areas.The steady-state photoluminescence results exhibit an obvious composition-related quenching ratio,revealing a strong coherence between the band offset and the charge transfer efficiency at the junction interface.Based on the achieved heterostructures,dual-channel backgate field-effect transistors were successfully designed and exhibited typical composition-dependent transport behaviors,and pure n-type unipolar transistors to ambipolar transistors were realized in such systems.The direct vapor growth of these novel vertical WS2(1−x)Se2x/SnS2 heterostructures could offer an interesting system for probing new physical properties and provide a series of layered heterostructures for high-quality devices.