Utilizing trapped charge at bilayer 2D MoS₂/SiO₂ interface for memory applications

Abstract

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 MoS2 flake. The MoS2 is 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/SiO2 interface. The MoS2 nano-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 consecutive IV sweeps. 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.

Nanoscale probing of surface potential landscape at MoS2/BP van der Waals p–n heterojunction

“…Van der Waal heterostructures with lateral or vertical stacking [3] and Type I, Type II, and Type III heterostructures based on the band alignments [4] are being explored for optoelectronic, valleytronic and photonic applications [5][6][7]. Layered molybdenum sulfide (MoS 2 ) and black phosphorus (BP) are perhaps the most popular 2D nanomaterials being explored by researchers for electronic applications [8,9]. MoS 2 is n-type semiconductor having high electron mobility and layer numberdependent band gap which varies from 1.2 eV to 1.8 eV as thickness decrease from bulk to monolayer [10].…”