A surface work function measurement technique utilizing constant deflected grazing electron trajectories: oxygen...

Area of Science:

• Surface science
• Materials science
• Physical chemistry

Background:

• Accurate work function measurement is crucial for understanding surface phenomena.
• Existing techniques can be destructive or limit simultaneous surface analysis.
• A non-invasive method is needed for in-situ work function monitoring.

Purpose of the Study:

• To present a novel, nondestructive in-vacuum technique for relative work function measurements.
• To demonstrate the technique's sensitivity, stability, and compatibility with other surface analysis methods.
• To investigate work function changes during molecular oxygen exposure on a Cu(001) surface.

Main Methods:

• Utilizes grazing incidence electron deflection above a planar sample surface in a vacuum.
• Employs two deflected electron beam detectors for feedback control of sample potential.
• Optimizes electron trajectories to minimize external magnetic field interference.

Main Results:

• Achieved work function measurement sensitivity and stability of ~10 mV at 1 Hz sampling rate.
• Demonstrated concurrent measurements of helium atom reflectivity and work function changes.
• Observed that work function measurements are more sensitive to initial oxygen uptake than final coverage.

Conclusions:

• The novel electron deflection technique provides a non-destructive, highly sensitive method for relative work function measurements.
• The technique allows for simultaneous surface characterization and avoids electron-induced sample modifications.
• This method is valuable for studying dynamic surface processes, such as gas adsorption, in real-time.