Molecular Switching Operation in Gate Constricted Interface of MoS$_2$ and hBN Heterostructure

TL;DR

This study demonstrates a molecular switch in a MoS2/hBN heterostructure, where charge transfer can be electrically controlled at a molecular level, enabling high on/off ratios and potential applications in atomically thin electronic devices.

Contribution

The paper reports the first observation of molecular-level charge transfer switching in van der Waals heterostructures, controlled via gate constriction and bias, with implications for room-temperature molecular electronics.

Findings

Charge transfer switching depends on local gate constriction and bias.

Exposing nitrogen dioxide gas modulates conductance with high on/off ratio.

First-principle calculations elucidate the molecular switching mechanism.

Abstract

Combined diverse two-dimensional (2D) materials for semiconductor interfaces are attractive for electrically controllable carrier confinement to enable excellent electrostatic control. We investigated the transport characteristic in heterointerface of multilayer molybdenum disulfide and hexagonal boron nitride (MoS$_2$/h-BN) to reveal that the charge transfer switching (CTS) is highly dependent on both the local gate constriction and bias in the channel. Notably, the CTS is shown to be controlled at a molecular level through electrotunable gated constriction. The resulting significant change in conductance due to exposing 100 parts-per-billion of nitrogen dioxide gas led to a high on/off ratio of 10 2 for completely switching off the channel thus, acting as a molecular switch. First-principle calculations further explained the mechanism of molecular CTS in the device. The molecular tunability of CTS has not been previously reported in any of the van der Waals semiconductor interfaces. Our finding opens avenues to exploit various atomically thin heterostructures for the mesoscopic transport phenomena towards molecular switching operation at room temperature.