Charge Transport in MoS₂/WSe₂ van der Waals Heterostructure with Tunable Inversion Layer

Abstract

Despite numerous studies on two-dimensional van der Waals heterostructures, a full understanding of the charge transport and photoinduced current mechanisms in these structures, in particular, associated with charge depletion/inversion layers at the interface remains elusive. Here, we investigate transport properties of a prototype multilayer MoS/WSe heterojunction via a tunable charge inversion/depletion layer. A charge inversion layer was constructed at the surface of WSe due to its relatively low doping concentration compared to that of MoS, which can be tuned by the back-gate bias. The depletion region was limited within a few nanometers in the MoS side, while charges are fully depleted on the whole WSe side, which are determined by Raman spectroscopy and transport measurements. Charge transport through the heterojunction was influenced by the presence of the inversion layer and involves two regimes of tunneling and recombination. Furthermore, photocurrent measurements clearly revealed recombination and space-charge-limited behaviors, similar to those of the heterostructures built from organic semiconductors. This contributes to research of various other types of heterostructures and can be further applied for electronic and optoelectronic devices.

Visualization of Local Conductance in MoS2/WSe2 Heterostructure Transistors

“…The positions of the characteristic Raman peaks on individual flakes as well as the HS overlap region ( Fig. 1c) are consistent with that reported in the literature 26,42,43 . The transfer and output characteristics of the HS device are plotted in Fig.…”

FeIn2S4 Nanocrystals: A Ternary Metal Chalcogenide Material for Ambipolar Field‐Effect Transistors

“…Based on this, the Schottky barrier height between FeIn 2 S 4 and Au is around 0.6–0.8 eV, which is not negligible for charge carrier transport. Through this barrier, carriers can tunnel through the interface by means of two phenomena: direct tunneling and Fowler–Nordheim (FN) tunneling 24. Two significantly different slopes are observed in the curve of current versus drain voltage in two different voltage regimes (Figure 5e(i),(ii) and Figure S6 (Supporting Information)), so it can be assumed that there is a Schottky barrier at the interface between the channel layer and the electrodes, in good agreement with the characterization results for FeIn 2 S 4 NCs (Table 1).…”

Near-Direct Bandgap WSe2/ReS2 Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

“…In contrast to pn junctions fabricated using inorganic doped semiconductors like Si, the forward bias current transport in vdW pn heterojunctions is dominated by tunnelling-based trap assisted (Shockley-Read-Hall, SRH) or direct (Langevin) recombination of majority carriers across the heterointerface. 6,47 The current transport due to Fowler-Nordheim tunnelling (FNT) through a triangular potential barrier is modelled by the equation: 48 is assumed to be near the valence band and EF_R to be near the conduction band. When forward biased, a positive voltage is applied to WSe2 and ReS2 is kept grounded.…”