Temperature dependent low energy electron microscopy study of Ge island growth on bareand Ga terminated Si(112)

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The pre-adsorption of Ga on Si(112) leads to a drastic change of the morphology ofsubsequently grown Ge islands. In contrast to the case for Ge growth on bare Si(112), evennanowire growth can be achieved on Ga terminated Si(112). Employing low energy electronmicroscopy and low energy electron diffraction, the initial phase of Ge nucleation and Geisland growth was systematically analysed for growth temperatures between 420 and610 °C, both on clean and on Ga terminated Si(112). In both cases the island density exhibits anArrhenius-like behaviour, from which diffusion barrier heights of about 1.3 and 1.0 eV canbe estimated for growth with and without Ga pre-adsorption, respectively. The Ge islandshape on the bare Si(112) surface is found to be nearly circular over the wholetemperature range, whereas the shapes of the Ge islands on the Ga terminated Si(112)become highly anisotropic for higher temperatures. Ge nanowires with sizes of up to2 µm along the direction are observed.