Investigation of semiconductor properties of Co/Si(111)-7 x 7 by AFM/KPFS

Studies of the physics underlying carrier transport characteristics and band bending of semiconductors are critical for developing new types of devices. In this work, we investigated the physical properties of Co ring-like cluster (RC) reconstruction with a low Co coverage on a Si(111)-7 x 7 surface at atomic resolution by atomic force microscopy/Kelvin probe force microscopy at 78 K. We compared the applied bias dependence of frequency shift between two types of structure: Si(111)-7 x 7 and Co-RC reconstructions. As a result, the accumulation, depletion, and reversion layers were identified in the Co-RC reconstruction by bias spectroscopy. For the first time, we found that Co-RC reconstruction on the Si(111)-7 x 7 surface shows semiconductor properties by Kelvin probe force spectroscopy. The findings of this study are useful for developing new materials for semiconductor devices.

Automated summary

Studies of the physics behind carrier transport characteristics and band bending in semiconductors are critical for the development of new devices. This study investigated the physical properties of Co ring-like cluster (RC) reconstruction on a Si(111)-7 x 7 surface at atomic resolution using atomic force microscopy/Kelvin probe force microscopy. The applied bias dependence of frequency shift was compared between Si(111)-7 x 7 and Co-RC reconstructions, and the accumulation, depletion, and reversion layers were identified in the Co-RC reconstruction. It was found for the first time that the Co-RC reconstruction on the Si(111)-7 x 7 surface exhibits semiconductor properties. These findings are valuable for the development of new materials for semiconductor devices.