Surface science lettersGa on Si(112): growth and energetics of thermal desorption

The growth of Ga overlayers on Si(112) has been studied using Auger electron spectroscopy and low-energy electron diffraction. The feasibility of the (112) surface as a template for the growth of Ga quantum well wires is also explored. For substrate temperatures between room temperature and 450°C we observe the Stranski-Krastanov growth mode in which islands form on top of one to two overlayers. Above 450°C a well-ordered overlayer structure yielding a (6 × 1) LEED pattern is observed. Once this overlayer structure is formed there is little or no change in the AES signal or LEED pattern with increasing deposition. Thermal desorption measurements from this overlayer coverage reveal a much higher desorption energy than from either the Ga islands or from Ga on Si(111) and Si(001) substrates. These results suggest that the Ga atoms are strongly bound in chains along the step edges of the facet surface.