Scanning-tunneling-microscope modifications of Cu(Ag)-chalcogenide glasses

Abstract

Chalcogenide glasses containing Cu and Ag were investigated using a scanning tunneling microscope (STM). Cu–As–Se and Ag–As–Se glasses exhibited different phenomena. When voltages applied to STM tips were low (| V|≤1 V), tunneling spectra in Ag–As–Se changed with scan speed of the tip voltages, while such a feature was not observed in Cu–As–Se. At high voltages (| V|≥3 V), geometrical surface modifications appeared in both glasses, but the shapes were different. In Ag–As–Se hills or holes were created, and in Cu–As–Se deformations were induced under negative tip voltages. Origins of these observations are discussed.