Ultrathin Three-Monolayer Tunneling Memory Selectors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• High-density memory arrays necessitate selector devices to prevent leakage current.
• Selectors require highly nonlinear current-voltage characteristics and excellent endurance.
• Tunneling-based selectors offer advantages over atomic/ionic motion mechanisms.

Purpose of the Study:

• To develop an ultrathin tunneling-based memory selector using 2D materials.
• To investigate the impact of heterojunction structure on device performance.
• To enhance the nonlinearity of memory selectors for improved functionality.

Main Methods:

• Fabrication of a three-monolayer-thick heterojunction using hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS2).
• Characterization of current-voltage (I-V) properties of the fabricated device.
• Experimental tuning of the MoS2 Fermi level to optimize device nonlinearity.

Main Results:

• An "H-shaped" energy barrier was formed within the h-BN/MoS2/h-BN heterojunction.
• The device exhibited nonlinear modulation of tunneling current with varying external voltage.
• Device nonlinearity was significantly improved from 10 to 25 by tuning the MoS2 Fermi level.

Conclusions:

• The study provides fundamental insights into tunneling mechanisms in atomically thin 2D heterojunctions.
• The developed 2D heterojunction selector demonstrates potential for high-endurance, high-density non-volatile memory.
• This work lays the groundwork for future advancements in 2D material-based memory technologies.