Versatile Post-Doping toward Two-Dimensional Semiconductors.

Murai, Yuya; Zhang, Shaochun; Hotta, Takato; Liu, Zheng; Endo, Takahiko; Shimizu, Hiroshi; Miyata, Yasumitsu; Irisawa, Toshifumi et al. · ACS Nano · 2021

basic_science · Level V

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Abstract

We have developed a simple and straightforward way to realize controlled postdoping toward 2D transition metal dichalcogenides (TMDs). The key idea is to use low-kinetic-energy dopant beams and a high-flux chalcogen beam simultaneously, leading to substitutional doping with controlled dopant densities. Atomic-resolution transmission electron microscopy has revealed that dopant atoms injected toward TMDs are incorporated substitutionally into the hexagonal framework of TMDs. The electronic properties of doped TMDs (Nb-doped WSe<sub>2</sub>) have shown drastic change and <i>p-</i>type action with more than 2 orders of magnitude increase in current. Position-selective doping has also been demonstrated by the postdoping toward TMDs with a patterned mask on the surface. The postdoping method developed in this work can be a versatile tool for 2D-based next-generation electronics in the future.