Contact Potential in Thin Metal Films

Abstract

Attempts were made to observe a work function variation with thickness of thin gold, platinum, and silver films. The films were vacuum deposited onto fused silica substrates at pressures of about 10⁻⁸ torr. The vibrating capacitor method was used to measure the contact potential difference between the films and a platinum reference surface as a function of film resistance. The measurements were carried out at pressures of 10⁻⁸−10⁻¹⁰ torr. The contact potential difference was found to be independent of film resistance in the range of 5 ohms/sq to 10⁸ ohms/sq.