High-Resolution NC-AFM Imaging and Analysis for Clean Diamond (001) Surfaces

Since the invention of the scanning tunneling microscopy (STM), atomic-resolution images of surfaces have greatly aided the understanding in the atomic scale. Diamond has garnered significant attention in recent years due to its potential use for field-effect transistors operating at high voltages, high temperatures, and high frequencies, owing to its wide bandgap. However, surface defects and adsorbed atoms hinder its stable performance as power devices. Investigating its surface structures using STM is exceptionally challenging due to the wide bandgap. The non-contact atomic force microscopy (NC-AFM), which employs atomic force for imaging, is considered as an optimal tool for obtaining atomic-resolution images of insulator surfaces. Nevertheless, single-atom-resolution images of clean diamond (001) surfaces have not been achieved.

In our experiments, we use silicon probes for NC-AFM employed in an active imaging technique, achieving the first single-atom resolution AFM images. As expected for the model calculated with DFT, the clean diamond (001) surface is stabilized in a reconstruction. The distance between the dimers has been carefully analyzed and will be discussed in the present. We also obtained high-resolution AFM images of dimer rows on clean diamond (001) surfaces. We anticipate the present results promote the future performance of diamond devices.