Solution-Phase Synthesis of Vanadium Intercalated 1T'-WS<sub>2</sub> with Tunable Electronic Properties.

Zhu, Kuixin; Tao, Yiyin; Clark, Daniel E; Hong, Wei; Li, Christina W · Nano Lett · 2023

basic_science · Level V

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Abstract

Metal ion intercalation into Group VI transition metal dichalcogenides enables control over their carrier transport properties. In this work, we demonstrate a low-temperature, solution-phase synthetic method to intercalate cationic vanadium complexes into bulk WS<sub>2</sub>. Vanadium intercalation expands the interlayer spacing from 6.2 to 14.2 Å and stabilizes the 1T' phase of WS<sub>2</sub>. Kelvin-probe force microscopy measurements indicate that vanadium binding in the van der Waals gap causes an increase in the Fermi level of 1T'-WS<sub>2</sub> by 80 meV due to hybridization of vanadium 3d orbitals with the conduction band of the TMD. As a result, the carrier type switches from p-type to n-type, and carrier mobility increases by an order of magnitude relative to the Li-intercalated precursor. Both the conductivity and thermal activation barrier for carrier transport are readily tuned by varying the concentration of VCl<sub>3</sub> during the cation-exchange reaction.