Electrostatic force characterization on InAs dot-covered n-type (001) GaAs surfaces by contact-mode atomic force microscopy with a conductive tip

Abstract

Atomic force microscopy was performed while applying an ac bias voltage between the tip and the sample to characterize the near surface band structures of InAs dot-covered n-type (001) GaAs. An electrostatic force of less than 10 pN was detected along with a clear electrostatic force images with lateral resolution better than 20 nm. The electrostatic force images of the different frequency components reveal that the gap width between the tip and the conductive region of the sample in the dot-covered area is smaller itself, and is less modulated by the bias voltage than that under the wetting layer.