Mechanism of Local Electric Oxidation on Two-Dimensional MoS2 for Resistive Memory Application

Abstract

The manipulation and mechanism of two-dimensional (2D) transition metal dichalcogenides (TMDs) by external electric field are extremely significant to the photoelectric properties for guiding their applications. Herein, the 2D MoS2 nanosheets were locally oxidated to form MoS2-MoO3 local heterojunctions by electric field from atomic force microscopy tip, which were further applied in mutilstate memristors for the proposal of NanoQR code. A modified thermal oxidation model has been derived through introducing Ohmic dissipation to reveal the mechanism of local electric oxidation on 2D MoS2. From current-voltage curves, the barrier height of MoS2 device showed an increase of 0.39 eV due to local oxidation after applying voltage for 480 s. Based on density-functional theory, the increase of barrier height was theoretical calculated as 0.38 eV between MoS2-MoS2 and MoS2-MoO3 supercells, supporting the formation of MoO3 under the local electric field. The manipulated 2D MoS2-MoO3 local heterojunctions were further applied as unprecedented mutilstate memory storage at the nanoscale, which induced the proposal of NanoQR code as strong-encryption information. The findings suggest a novel strategy on precisely controlling local electric oxidation on 2D TMDs to manipulate the properties for application of photoelectric memory nanodevices.

Keywords: two-dimensional MoS2, local electric oxidation, barrier height, memory, NanoQR code