Fast transient charge trapping in salt-aided CVD synthesized monolayer MoS2 field-effect transistor

TL;DR

This study investigates fast transient charge trapping in high-quality salt-assisted CVD MoS2 FETs, revealing methods to enhance mobility and achieve hysteresis-free operation through pulse techniques and DFT analysis.

Contribution

It introduces a pulse I~V methodology combined with DFT calculations to understand and control charge trapping in CVD MoS2 transistors, improving device performance.

Findings

Mobility increased by up to ~100% with short pulses

Hysteresis-free transfer characteristics achieved

Fast and slow charge trapping phenomena characterized

Abstract

Atomically thin semiconductors have versatile future applications in the information and communication technologies for the ultimate miniaturization of electronic components. In particular, the ongoing research demands not only a large-scale synthesis of pristine quality monolayer MoS2 but also advanced nanofabrication and characterization methods for investigation of intrinsic device performances. Here, we conduct a meticulous investigation of the fast transient charge trapping mechanisms in field-effect transistors (FETs) of high-quality CVD MoS2 monolayers grown by a salt-driven method. To unfold the intrinsic transistor behavior, an amplitude sweep pulse I~V methodology is adapted with varying pulse widths. A significant increase in the field-effect mobility up to ~100% is achieved along with a hysteresis-free transfer characteristic by applying the shortest pulse. Moreover, to correlate these results, a single pulse time-domain drain current analysis is carried out to unleash the fast and slow transient charge trapping phenomena. Furthermore, rigorous density functional theory (DFT) calculations are implemented to inspect the effects of the Schottky barrier and metal-induced gap states between drain/source electrode and MoS2 for the superior carrier transport. Our findings on the controllable transient charge trapping mechanisms for estimation of intrinsic field-effect mobility and hysteresis-free transfer characteristic in salt-assisted CVD-grown MoS2 FETs will be beneficial for future device applications in complex memory, logic, and sensor systems.