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

Area of Science:

• Materials Science
• Nanoscience
• Condensed Matter Physics

Background:

• Two-dimensional (2D) materials like molybdenum disulfide (MoS2) exhibit unique electronic properties.
• Understanding charge transport and trapping mechanisms is crucial for developing novel electronic devices.

Purpose of the Study:

• To investigate the charge injection process into single bilayer 2D MoS2 flakes.
• To elucidate charge trapping/de-trapping mechanisms at the MoS2/SiO2 interface.
• To demonstrate memory behavior in MoS2 flakes.

Main Methods:

• Utilized conductive atomic force microscopy (cAFM) for nanoscale electrical measurements.
• Employed exfoliated bilayer MoS2 flakes on ultra-thin SiO2/Si substrates.
• Performed local current-voltage (IV) measurements.

Main Results:

• Observed an adjustable potential barrier for charge trapping at the MoS2/SiO2 interface.
• Demonstrated a voltage window (ΔV ~ 1.8 V) between consecutive IV sweeps at 2 nA.
• Differentiated between two distinct states, indicating memory behavior.

Conclusions:

• The MoS2 nano-flake acts as a potential barrier, confining injected charges at the interface.
• The observed memory effect is attributed to charge entrapment and its influence on tunneling.
• Results provide insights into the physics of charge trapping and tunneling in 2D materials.