Utilizing trapped charge at bilayer 2D MoS₂/SiO₂interface for memory applications

In this work we use conductive atomic force microscopy (cAFM) to study the charge injection process from a nanoscale tip to a single isolated bilayer 2D MoS₂flake. The MoS₂is exfoliated and bonded to ultra-thin SiO₂/Si substrate. Local current-voltage (IV) measurements conducted by cAFM provides insight in charge trapping/de-trapping mechanisms at the MoS₂/SiO₂interface. The MoS₂nano-flake provides an adjustable potential barrier for embedded trap sites where the charge is injected from AFM tip is confined at the interface. A window of (ΔV∼ 1.8 V) is obtain at a reading current of 2 nA between two consecutiveIVsweeps. This is a sufficient window to differentiate between the two states indicating memory behavior. Furthermore, the physics behind the charge entrapment and its contribution to the tunneling mechanisms is discussed.