Computational Assessment of <i>I</i>-<i>V</i> Curves and Tunability of 2D Semiconductor van der Waals Heterostructures.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39841577.
- Also identified by DOI 10.1021/acs.nanolett.4c06076 and PMC identifier 11803710.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDs) have received significant interest for use in tunnel field-effect transistors (TFETs) due to their ultrathin layers and tunable band gap features. In this study, we used density functional theory (DFT) to investigate the electronic properties of six TMD heterostructures, namely, MoSe<sub>2</sub>/HfS<sub>2</sub>, MoTe<sub>2</sub>/ZrS<sub>2</sub>, MoTe<sub>2</sub>/HfS<sub>2</sub>, WSe<sub>2</sub>/HfS<sub>2</sub>, WTe<sub>2</sub>/ZrS<sub>2</sub>, and WTe<sub>2</sub>/HfS<sub>2</sub>, focusing on variations in band alignments. We demonstrate that WTe<sub>2</sub>/ZrS<sub>2</sub> and WTe<sub>2</sub>/HfS<sub>2</sub> have the smallest band gaps (close to 0 or broken) from the considered set. Furthermore, combining DFT with the nonequilibrium Green's function method (DFT-NEGF), we analyzed the output <i>I</i>-<i>V</i> characteristics, revealing increased current as band gap closes across all studied heterostructures. Notably, WTe<sub>2</sub>/ZrS<sub>2</sub> and WTe<sub>2</sub>/HfS<sub>2</sub> show a potential negative differential resistance (NDR) even without a broken gap. Importantly, the inclusion of a p-doped gate effect in WTe<sub>2</sub>/ZrS<sub>2</sub> enhances the current flow and band-to-band tunneling. The rapidly increasing tunneling current under low applied voltage indicates that the WTe<sub>2</sub>/ZrS<sub>2</sub> and WTe<sub>2</sub>/HfS<sub>2</sub> heterostructures are promising for applications in TFETs.