Qing Zhang1,2,Dechao Geng3,Wei Chen1,2,Wenping Hu1,3
Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University1,Department of Chemistry, National University of Singapore2,Department of Chemistry, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering3
Qing Zhang1,2,Dechao Geng3,Wei Chen1,2,Wenping Hu1,3
Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University1,Department of Chemistry, National University of Singapore2,Department of Chemistry, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering3
Chemical techniques for modifying the intrinsic optoelectronic properties of transition metal dichalcogenides (TMDs) have provided tremendous flexibility for multi-functional electronics. The innovative product created by combining two chemical strategies, substitutional doping and heterostructure, is predicted to tune TMD band topologies over a wide range. However, because of the advanced equipment and the unavoidable cross-contamination problem, the regulated synthesis of doped material/pure material heterostructures remains a challenge. To address the issues, a simple dual additives-assisted chemical vapor deposition (DACVD) approach is proposed to synthesis a new type of heterostructure formed by W-doped MoS<sub>2</sub> and pure MoS<sub>2</sub> in a controlled manner. Molten salts lower the melting point of metal oxide precursors, while oxygen plasma pre-treatment on the substrate creates a defect-free surface that allows only pure MoS<sub>2</sub> to be deposited. Following that, doped materials are grown in sub-sequential layers in a controlled manner. The doping ratio can reach as high as 17%. The multilayered pyramid structure reduces contact resistance sufficiently, thus the mobility of multilayer heterostructure is superior to that of conventionally CVD-produced monolayer MoS<sub>2</sub> and multilayer MoS<sub>2</sub>. Furthermore, the heterostructure exhibits diode-like characteristics, with a rectification ratio of up to 3.5 × 10<sup>3</sup>. This work provides ideas and experimental cases for the preparation and application of novel heterostructures.