Diamond homoepitaxial growth on (111) substrate investigated by scanning tunneling microscope

Epitaxial films were grown on diamond(111) substrates by microwave-plasma-assisted chemical vapor deposition, and their surfaces were studied by scanning tunneling microscope (STM). STM images with atomic order resolution were obtained, and showed 1×1 periodicity, which was also observed by low-energy electron diffraction. 〈112〉 single bilayer steps, 〈112̄〉 single bilayer steps, and 〈112〉 double bilayer steps were observed, and the majority of the steps were found to be of the first type. Steps were found to be very straight in the atomic scale, and there were suggestions of the incorporation of carbon atoms at the kinks. Even a small island with a nanometer order size showed a triangular shape surrounded by three 〈112〉 single bilayer steps.