Room temperature observation of point defect on gold surface using thermovoltage mapping

Abstract

In this work, we apply thermovoltage imaging using scanning tunneling microscope to observe atomic scale surface imperfections at room temperature. Thermovoltage mapping can provide high resolution (down to 1 nm) images of standing waves in metal at room temperature, thus avoiding the need for low temperature scanning tunneling microscopy for the investigation of the standing waves. In order to generate a thermovoltage between the sample and tip, the sample (Au(1 1 1)) is heated to about 40 °C above the room temperature and surface scanning is performed. Heating the sample is simpler than heating the tip by laser irradiation. The thermovoltage technique can be applied to estimate surface defect density and the severity of the surface defects in materials, which can be a useful tool for the reliability study of nano-scale materials and devices.