Polarity Control in Ge Nanowires by Electronic Surface Doping

Area of Science:

• Nanoscale electronic and photonic devices
• Semiconductor physics
• Materials science

Background:

• Nanostructure properties are highly sensitive to size, geometry, and surface effects due to high surface-to-volume ratios.
• Germanium (Ge) offers high electron and hole mobility, crucial for extending device performance beyond miniaturization limits.
• Charge trapping at surfaces severely limits the application of Ge-based nanodevices.

Purpose of the Study:

• To demonstrate that electrostatic gating can control surface trap populations in Ge nanowires.
• To achieve effective surface doping in Ge nanostructures.
• To understand charge-trapping-induced transport mechanisms in Ge nanostructures.

Main Methods:

• Fabrication and characterization of Ge nanowires.
• Application of electrostatic gating to control surface trap states.
• Electrical transport measurements to analyze device behavior.

Main Results:

• Demonstrated reproducible control of surface trap population in Ge nanowires using electrostatic gating.
• Achieved effective surface doping, leading to a transition from hole- to electron-dominated transport.
• Observed electron-driven negative differential resistance, confirming the shift in dominant charge carriers.

Conclusions:

• Electrostatic gating is a viable method for effective surface doping and controlling transport in Ge nanowires.
• Understanding and mitigating charge trapping effects are critical for advancing Ge nanodevice technology.
• This work provides significant insights into charge-trapping-induced transport phenomena in Ge nanostructures.