Room Temperature Gold-Vacuum-Gold Tunneling Experiments.

Area of Science:

• Quantum Mechanics
• Condensed Matter Physics
• Surface Science

Background:

• Quantum mechanical tunneling is a fundamental phenomenon.
• Understanding electron tunneling is crucial for nanoscale electronic devices.
• Previous studies lacked methods to independently determine electrode work functions within tunneling experiments.

Purpose of the Study:

• To experimentally demonstrate and quantify electron quantum tunneling between gold electrodes in vacuum.
• To investigate the relationship between tunneling current and electrode spacing.
• To deduce electrode work functions and analyze factors influencing current-voltage characteristics.

Main Methods:

• Measured tunneling current between gold electrodes at fixed voltages (0.1 V, 0.01 V) while varying electrode spacing from 2.0 nm to contact.
• Obtained current-voltage (I-V) characteristics for electrode spacings below 2.0 nm.
• Performed numerical calculations using free-electron model, image-potential reduced barrier, and WKB approximation.

Main Results:

• Observed over five orders of magnitude change in tunneling current for a 1.2 nm change in electrode spacing.
• Successfully deduced electrode work functions from experimental parameters.
• Analysis indicated van der Waals and electrostatic forces significantly impact I-V characteristics, with potential tunneling areas as small as 10^-16 m^2.

Conclusions:

• Experimental validation of electron quantum tunneling between gold electrodes.
• Developed a method to determine work functions independently within tunneling experiments.
• Highlighted the significant influence of intermolecular forces on nanoscale tunneling behavior.