Electronic structure of the Ge/Si(1 0 5) hetero-interface: an ARPES and DFT study


We present a joint experimental and theoretical study of the electronic properties of the rebonded-step reconstructed Ge/Si(1 0 5) surface which is the main strained face found on Ge/Si(0 0 1) quantum dots and is considered a prototypical model system for surface strain relaxation in heteroepitaxial growth. 
P.M. Sheverdyaeva et al., J. Phys. Cond. Mat. 30 (2018)

Using a vicinal surface as a model system for obtaining a stable single-domain film structure with large terraces and rebonded-step surface termination, we realized an extended and ordered Ge/Si planar hetero-junction suitable for direct study with angle-resolved photoemission spectroscopy.

At the coverage of four Ge monolayers photoemission spectroscopy reveals the presence of 2D surface and film bands displaying energy-momentum dispersion compatible with the 5  ×  4 periodicity of the system. The good agreement between experiment and first-principles electronic structure calculations confirms the validity of the rebonded-step structural model. The direct observation of surface features within 1 eV below the valence band maximum corroborates previously reported analysis of the electronic and optical behavior of the Ge/Si hetero-interface.



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