Controllable Doping in 2D Layered Materials.

Wang, Zhen; Xia, Hui; Wang, Peng; Zhou, Xiaohao; Liu, Chunsen; Zhang, Qinghua; Wang, Fang; Huang, Menglin et al. · Adv Mater · 2021

basic_science · Level V

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Abstract

For each generation of semiconductors, the issue of doping techniques is always placed at the top of the priority list since it determines whether a material can be used in the electronic and optoelectronic industry or not. When it comes to 2D materials, significant challenges have been found in controllably doping 2D semiconductors into p- or n-type, let alone developing a continuous control of this process. Here, a unique self-modulated doping characteristic in 2D layered materials such as PtSSe, PtS<sub>0.8</sub> Se<sub>1.2</sub> , PdSe<sub>2</sub> , and WSe<sub>2</sub> is reported. The varying number of vertically stacked-monolayers is the critical factor for controllably tuning the same material from p-type to intrinsic, and to n-type doping. Importantly, it is found that the thickness-induced lattice deformation makes defects in PtSSe transit from Pt vacancies to anion vacancies based on dynamic and thermodynamic analyses, which leads to p- and n-type conductance, respectively. By thickness-modulated doping, WSe<sub>2</sub> diode exhibits a high rectification ratio of 4400 and a large open-circuit voltage of 0.38 V. Meanwhile, the PtSSe detector overcomes the shortcoming of large dark-current in narrow-bandgap optoelectronic devices. All these findings provide a brand-new perspective for fundamental scientific studies and applications.