Resolving microscopic interfaces in Si(1-x)Ge(x) alloy nanowire devices.

Area of Science:

• Materials Science
• Nanotechnology
• Electrical Engineering

Background:

• Silicon-germanium (SiGe) alloy nanowires are promising for electronic devices.
• Understanding contact metal effects on SiGe nanowire properties is crucial for device optimization.

Purpose of the Study:

• To investigate the impact of different electrode materials (Ni vs. Ni/Au) on the electrical transport characteristics of SiGe alloy nanowires.
• To identify the origin of the observed resistance switching effect in these nanowire devices.

Main Methods:

• Fabrication of SiGe alloy nanowire devices with Ni and Ni/Au electrodes.
• Annealing of devices at varying temperatures (specifically 400°C).
• Electrical transport measurements and Transmission Electron Microscopy (TEM) analysis.

Main Results:

• Electrical transport properties were highly dependent on annealing temperature and contact metals.
• Ni/Au-contacted devices annealed at 400°C exhibited p-type transistor behavior and a notable resistance switching effect.
• Ni-contacted devices did not show resistance switching.
• TEM analysis revealed the presence of Au atoms adjacent to the SiGe nanowire in devices exhibiting resistance switching.

Conclusions:

• The presence of gold at the interface between the electrode and the SiGe alloy nanowire is critical for the observed hysteretic resistance switching effect.
• The choice of contact metal significantly influences the electrical properties and functionality of SiGe alloy nanowire devices.