Ultrafast and stable phase transition realized in MoTe₂-based memristive devices

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional transition metal dichalcogenides exhibit unique properties due to their thinness and polymorphism.
• Phase engineering is crucial for tailoring material properties for electronic applications.

Purpose of the Study:

• To achieve electric-field-induced controllable phase transitions in MoTe2 memristive devices.
• To investigate the stability, speed, and environmental resilience of these phase transitions.

Main Methods:

• Fabrication of MoTe2 memristive devices.
• Characterization of resistive switching behavior under various conditions.
• In situ Raman spectroscopy to analyze phase transitions.
• Density functional theory (DFT) calculations to understand the mechanism.

Main Results:

• Stable bipolar resistive switching with high endurance (>10^5 cycles) and retention (>10^5 s at 85 °C).
• Ultrafast switching speeds (SET ~5 ns, RESET ~10 ns).
• Robust performance in air, vacuum, and oxygen, with excellent long-term stability in air.
• Phase transition between semiconducting 2H and metallic 1T' phases confirmed as the switching mechanism.

Conclusions:

• Electric-field-induced phase transition in MoTe2 enables reliable and ultrafast memristive devices.
• Te vacancies play a key role in facilitating the phase transition.
• These findings open avenues for novel phase-transition-based electronic devices.