Low-Power Switching through Disorder and Carrier Localization in Bismuth-Doped Germanium Telluride Phase Change...

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Electronics

Background:

• Phase Change Memory (PCM) typically requires high current densities for crystal-amorphous transitions via melt-quench.
• Alternative low-energy amorphization pathways, such as defect-assisted processes, are being explored to reduce power consumption.

Purpose of the Study:

• To investigate the use of bismuth doping in GeTe nanowires to reduce amorphization energy costs.
• To establish the role of carrier localization effects in facilitating low-energy amorphization.

Main Methods:

• Fabrication of Bi-doped GeTe nanowires.
• Electrical characterization to measure RESET current densities.
• Analysis of carrier localization and carrier-lattice coupling effects.

Main Results:

• Achieved RESET current densities as low as ~0.3 MA cm⁻² in 8% Bi-doped GeTe nanowires, a ~3-fold reduction compared to undoped nanowires.
• Demonstrated significantly lower switching currents compared to GeTe thin film devices (~50 MA cm⁻²).
• Observed good switching reversibility and the existence of intermediate resistance states.

Conclusions:

• Bismuth doping effectively engineers carrier localization, enhancing carrier-lattice coupling for efficient amorphization without melting.
• Low-power switching and multiple resistance states in Bi-doped GeTe nanowires are promising for non-volatile memory and neuromorphic computing.