A high resolution probe for scanning electrostatic potential profiles across surfaces

Abstract

An electrostatic probe with spatial resolution of 50 mu m has been developed to study the potential variation along a surface. A turntable arrangement enables surfaces to be scanned at rates of 1.8-16 m s-1; the probe yields a precision of 20 mV for a single pass. Calibration of the instrument using a test grating is described. A study of clean metal surfaces contaminated by fingerprints has shown surface potential variations as large as 400 mV.