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2D Memory Selectors with Giant Nonlinearity Enabled by Van der Waals Heterostructures
Xiaofan Wang1, Ruixi Qiao1, Huan Lu1
1Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
Small (Weinheim an Der Bergstrasse, Germany)
|April 4, 2024
Summary
A novel graphene/hBN/WSe2 heterostructure memory selector achieves record high nonlinearity for 2D selectors. This breakthrough enables high-density storage devices by preventing leakage currents and crosstalk.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- High nonlinearity and bipolarity in selectors are crucial for one-selector-one-resistor crossbar arrays.
- Miniaturization challenges have limited the development of selectors with sufficient nonlinearity.
- Leakage currents and crosstalk hinder the performance of high-density storage devices.
Purpose of the Study:
- To develop a high-performance memory selector with enhanced nonlinearity and bipolarity.
- To address the scarcity of selectors suitable for miniaturized, high-density storage applications.
- To investigate the charge transport mechanisms in novel 2D heterostructures.
Main Methods:
- Fabrication of a graphene/hBN/WSe2 heterostructure.
- Characterization of the selector's electrical properties, including current-voltage (I-V) curves.
- Analysis of tunneling mechanisms (direct tunneling and Fowler-Nordheim tunneling).
- Evaluation of device stability over 70,000 switching cycles.
Main Results:
- The heterostructure selector exhibits nonlinearity ranging from ≈10^3–10^4 (forward bias) and ≈300–10^5 (reverse bias) across 300–80 K.
- Achieved the highest reported nonlinearity among two-dimensional (2D) selectors.
- Demonstrated excellent bipolarity due to comparable hole and electron tunneling barriers.
- Tunable charge transport polarity (N-type, P-type, or bipolar) by adjusting bias.
- No degradation observed after 70,000 switching cycles.
Conclusions:
- The graphene/hBN/WSe2 heterostructure represents a promising high-performance memory selector.
- The device's high nonlinearity and bipolarity overcome limitations in current selectors.
- This advancement facilitates the integration of 2D selectors into advanced memory devices.
- The findings pave the way for next-generation high-density non-volatile memory.
