Scanning tunneling microscopy study of the Er/Ge(111) c(2×8) interface

Scanning tunneling microscopy (STM) is used to study the Er interaction on the Ge(111) substrate reconstructed c(2×8). In the submonolayer range, a homogeneous two-dimensional (2D) (1×1) reconstructed island distribution is observed for an Er deposit at room temperature with an additional annealing at 500 °C. However, when Er is deposited on substrate held at 500 °C, a significant modification in the surface morphology has been observed: 2D islands are accumulated at the step edges due to the high Ge and Er atom mobility. Moreover, for temperature under 500 °C, STM images have revealed the presence of metastable rod-shaped islands. Above 1 ML Er deposit, the interface displays a thin film reconstructed √3×√3R30° with a layer-by-layer growth mode.