Microscale Contact Charging on a Silicon Oxide

Abstract

In this study, we investigated contact charging and its dissipation on a silicon oxide surface using a reproducible and controllable contact charging method. As a result, we found that negative charge has three stages of both contact charging and charge dissipation, while positive charge has only one stage. By keeping on contact charging further, negative charge became high density, i.e., a solid phase of charges, on the silicon oxide surface even at room temperature in air. Further, we imaged point charge and charge distribution of free electrons on n+-GaAs(110) cleaved surface with atomic resolution using an electrostatic force microscope (EFM) combined with a noncontact atomic force microscope (NC-AFM). Moreover, we also imaged contact potential difference on Si(111)7×7 and Si(111)5√3×5√3-Sb with atomic resolution using a Kelvin probe force microscope (KPFM) combined with NC-AFM.