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The Ge growth behaviour on the 3$\times $3 Si-rich surface termination of 4H-SiC(0001) has been investigated in this study. After the deposit of one Ge monolayer at room temperature by molecular beam epitaxy, the film is submitted to isochronal annealing cycles up to 1000°C. A phase separation between Si and Ge is observed during the annealing process accompanied by successive 2D$/$3D and unusual 3D$/$2D transitions for both elements. Si and Ge struggle for wetting the bare surface in order to minimize its surface energy. This behaviour seems also to be related to the strain difference induced by the misfit of Si ($\sim $25%) and Ge (∼30%) with the 4H-SiC(0001) substrate.

The electronic structure of germanene is investigated by high resolution photoemission and density functional theory calculations. The core level Al 2p and Ge 3d lines are measured on germanene grown on Al(111) by using synchrotron radiation. The Ge 3d line is shifted toward the low binding energies with respect to bulk Ge, and shows three components, reflecting the sites multiplicity of the germanene atomic structure. The calculations reveal a sizable charge localization at the germanene/Al(111) interface, a charge transfer from the Al surface atoms to the germanene, and the existence of three nonequivalent Ge sites with three different atomic Bader charges, in agreement with the photoemission measurements.

The Ge growth behaviour on the 3?3 Si-rich surface termination of 4H-SiC(0001) has been investigated in this study. After the deposit of one Ge monolayer at room temperature by molecular beam epitaxy, the film is submitted to isochronal annealing cycles up to 1000?C. A phase separation between Si and Ge is observed during the annealing process accompanied by successive 2D/3D and unusual 3D/2D transitions for both elements. Si and Ge struggle for wetting the bare surface in order to minimize its surface energy. This behaviour seems also to be related to the strain difference induced by the misfit of Si (? 25%) and Ge (?30%) with the 4H-SiC(0001) substrate.

PtSi/p-strained-Si1-xGex(x=0.19 and x=0.29) Schottky barrier diodes have been fabricated and characterized for the determination of barrier height, ideality factor and the interface state density distribution with energy. Diodes having an epitaxial layer thickness of 20 and 52 nm were modeled with emphasis on comparison with experiment. To achieve better agreement with experimental data, an interfacial layer and associated series resistance were included in the model. The capacitance–voltage (C–V) technique has been used for the determination of the energy distribution of interface state density. The interface state density distribution for the Si0.81Ge0.19and Si0.71Ge0.29diodes is found to decrease with increasing energy from the valence band edge.