Solution-Phase Synthesis of Vanadium Intercalated 1T′-WS<sub>2</sub> with Tunable Electronic Properties
Kuixin Zhu, Yiyin Tao, D. Clark, Wei Hong, Christina Li
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 2 . Vanadium intercalation expands the interlayer spacing from 6.2 to 14.2 Å and stabilizes the 1T′ phase of WS 2 . 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 2 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 3 during the cation-exchange reaction.