Conductivity Modulation of a Slit Channel in a Monolayer MoS₂ Homostructure

The 1D-edge structure can potentially demonstrate higher conductivity in 2D materials because of dangling bonds and symmetry breaking. Studies use edge contact to circumvent the contact-scaling problem in 2D field-effect transistors (FETs) but with a rather complicated device fabrication process. Herein, a new concept is proposed directly using edges as the modulated channel, realized in a simple monolayer MoS₂ homostructure. When two 1D edges lie close to each other, they form a slit, which may demonstrate distinctive electronic features. The local conductivity along naturally and artificially created slits in monolayer MoS₂ is evaluated using noninvasive scanning microwave impedance microscopy with high spatial resolution. It is found that the two edges of the slits can show dramatically different conductivity due to the potential difference between the two parts separated by the slit, which can be controlled independently by the back-gate voltage and scanning conditions. Even when the back-gate voltage is off, the potential difference across the slit can retain, which makes it nonvolatile. This feature enables a MoS₂ flake to work as a homostructure device, in which the slit can perform as an efficient channel. The findings provide an alternative perspective of using slit as a new approach for 2D electronic devices.