Metal-semiconductor nanocontacts: silicon nanowires

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Silicon nanowires are promising for nanoelectronic devices.
• Understanding their electrical properties is crucial for device applications.
• Contact effects significantly influence nanowire conductivity.

Purpose of the Study:

• To investigate the electronic transport properties of silicon nanowires.
• To analyze the impact of wire length and contacts on conductance.
• To explore the formation of Schottky barriers in silicon nanowires.

Main Methods:

• Large-scale local-density-functional simulations were employed.
• Simulations considered silicon nanowires of varying lengths (0.6 nm and 2.5 nm).
• The study analyzed the effects of aluminum electrodes and passivation.

Main Results:

• Short silicon nanowires (approx. 0.6 nm) are fully metallized, showing finite conductance (approx. e^2/h).
• Longer silicon nanowires (approx. 2.5 nm) develop nanoscale Schottky barriers, 40-90% higher than bulk values.
• Electrical transport is dependent on doping and gate voltages, with conductance spectra showing interference resonances.

Conclusions:

• The length of silicon nanowires critically determines their electronic transport characteristics.
• Schottky barrier formation at contacts significantly impacts conductance in longer nanowires.
• Simulations provide insights into the quantum transport phenomena in silicon nanowires.