Ultrasensitive molecular interaction in MoS₂-graphene hybrid structure <i>via</i> electrostatic control

Following the discovery of graphene, other 2D materials such as TMDs offer great potential for future sensing devices because of the high surface-to-bulk ratio. Moreover, electronic transport in vertically stacked atomically thin heterojunctions of 2D materials are extremely sensitive to the surrounding atmosphere, thus allowing their exploration in molecular sensing applications. We report the fabrication of designed vdW interfaces of few-layer graphene and MoS₂ in vertical heterojunction and evaluation of electrical and molecular interaction. The few-layer MoS₂-graphene with vertically stacked hybrid shows a non-linearity in the drain current due to barrier formation at the interface that can be modulated by an external electric field. The hetero p-n junction between MoS₂ on graphene reveals superior molecular interaction with a high sensitivity of 18% at 10 ppb level of nitrogen dioxide in transfer characteristics near accumulation region at room temperature. We further observed that the recovery time of the device can be tuned using the switching behavior of the device depicting an overall superior sensing capability leading to an excellent advancement in sensing devices. Our findings offer significant insight into the MoS₂-graphene heterostructure for molecular interaction.