Interface bonding in silicon oxide nanocontacts: interaction potentials and force measurements.

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Understanding nanoscale interface bonding is crucial for materials adhesion and friction.
• Silicon oxide surfaces are ubiquitous in microelectronics and nanotechnology.

Purpose of the Study:

• To investigate the atomic nature and size dependence of interface bonding between silicon oxide nanoscale surfaces.
• To compare experimental measurements with theoretical models for nanocontact interactions.

Main Methods:

• Utilized atomic force microscopy (AFM) to measure experimental force curves in vacuum.
• Employed various interaction potentials (Morse, embedded atom model, Lennard-Jones) within reaction rate theory for numerical simulations.
• Analyzed bonding forces as a function of nanocontact size and stretching speed.

Main Results:

• Lennard-Jones potential, representing van der Waals interactions, accurately describes dry silicon oxide nanocontacts.
• Thermal-induced fluctuations significantly influence bonding in small nanocontacts (<10^3 nm^2).
• Dispersive surface energy and effective contact area, affected by stretching speed, are critical factors.

Conclusions:

• Van der Waals interactions are the primary bonding mechanism for dry silicon oxide nanocontacts.
• Contact weakening, characterized by a negative aging coefficient, occurs with increased time in the attractive regime, especially at low stretching speeds.
• The findings are applicable to other nanoscale materials adsorbed on silicon oxide surfaces.