Investigations of titanium nanostructures on Si(111) 7x7 by means of scanning tunnelling microscopy and spectroscopy

The aim of this paper were investigations of the growth of Ti nanostructures created by means of an electron gun on Si(111)-(7x7) with the coverage below 0.1 ML. Titanium was deposited on the Si substrate at 673 K. The Ti nanostructures after deposition and subsequent annealing processes were imaged in situ by means of UHV STM. The current imaging tunnelling spectroscopy (CITS) showed a contrast between the semiconducting substrate and Ti nanostructures. Some of the I V characteristics revealed the step-like character typical for the quantum size or Coulomb blockade effects. Annealing of the samples in the range of 673 K to 943 K led to appearing of the r19xr19 reconstruction. This reconstruction appeared at the cost of Ti nanostructures as a result of Ti atoms diffusion into Si sublayers.