Van der Waals-integrated crossbar arrays with adjustable atomic-scale channels for ultralow-power imaging

Abstract

The van der Waals (vdWs) integration of two-dimensional (2D) materials offers a versatile fabrication possibility for next-generation image sensors. However, there is a conflict between the desired small channel length and lateral device structures, superseding the depletion region, with a large footprint. Here, we propose a vdWs-integrated crossbar array structure utilizing a vertical 1T′/2H-MoTe₂/ITO structure for visible and near-infrared imaging. Such a crossbar design employs 2H-MoTe₂ layers as a vertical and adjustable atomic-scale channel with a large illumination area, which in turn effectively enhances the photoresponse. Additionally, the asymmetric electrode contacts consist of an ohmic contact in the 1T′/2H-MoTe₂ homojunction and a Schottky contact on the other side, contributing to self-powered photodetection. With these designs, the self-powered responsivity and detectivity reach 4.6 A W⁻¹ and 5.8 × 10¹³ cm Hz¹ᐟ²W⁻¹ with 23-nm channel thickness. This vdWs-integrated image sensor provides an alternative strategy for solving optimal performance and integration problems of 2D materials for the advancement of optoelectronics.