Piezoelectric driven Kelvin probe for contact potential difference studies

Abstract

A convenient piezoelectric driven Kelvin probe for the measurement of work function changes is described. The probe has a simple construction, is small, bakeable, and can be mounted on any 35‐mm‐i.d. UHV flange. As the piezoelectric device is inside the vacuum chamber, only one electrical feedthrough is needed for operating the probe. The distance between reference electrode and sample can be varied within ±0.5 mm simply by applying a dc voltage to the piezoelectric device in addition to the ac oscillator‐driving voltage, not requiring any mechanical driving and feedthrough provisions. The probe was tested studying the adsorption of O₂ on Pt(111). The sensitivity for contact potential measurements is better than 0.1 mV at a response time of 10 sec.