Investigation of atomic surface potential on Si(111)-7×7 surface by high-frequency heterodyne-Kelvin probe force microscopy

Abstract

The surface potential on n-type Si(111)-7 × 7 surface was measured at 78 K using high-frequency heterodyne-Kelvin probe force microscopy (HF-he-KPFM) method with atomic resolution. By comparing VCPD images obtained from conventional KPFM and HF-he-KPFM, we found that frequency dependence of carrier emission and capture of surface states on Si(111)-7 × 7 surface. Furthermore, donor- and accepter-like surface states on different atom position of Si(111)-7 × 7 surface are distinguished. In addition, the electric field effect of high-low Kelvin probe force spectroscopy (KPFS) was analyzed, and the dissipative force was revealed in the high-frequency KPFS. These findings underscore the potential of HF-he-KPFM as a promising method for studying semiconductor properties such as surface potential, band bending and capacitance.