Scanning tunneling microscopy study of the growth and self-organization of Ge nanostructures on vicinal Si(111) surfaces

The initial stages of Ge growth on Si(111) vicinal surfaces tilted in the $\overline 1 \overline 1 2$ ] and $11\overline 2 $ ] directions were studied in situ in the temperature range 350–500°C using scanning tunneling microscopy. It was shown that, at low Ge deposition rates of 10^?2 to 10^?3 BL/min, ordered Ge nanowires can form on surfaces tilted in the $\overline 1 \overline 1 2$ ] direction under conditions of step-layered growth. The height of a nanosized Ge wire is one or three interplanar distances and is determined by the initial height of a silicon step. It was established that, during epitaxial growth, steps with a $11\overline 2 $ ] front are replaced by steps with a $\overline 1 \overline 1 2$ ] front. As a result, the step edge is serrated and the formation of smooth nanosized Ge wires uniform in width is hampered on the serrated Si(111) surfaces tilted in the $11\overline 2 $ ] direction.