Electronic structure of the Ge/Si(105) hetero-interface

TL;DR

This study investigates the electronic structure of Ge/Si(105) hetero-interfaces, revealing ordered surface features and validating a structural model through experimental and computational methods, enhancing understanding of their electronic and optical properties.

Contribution

The paper provides combined experimental and theoretical analysis confirming the rebonded-step structural model of Ge/Si(105) hetero-interfaces.

Findings

Presence of two-dimensional surface and film bands with 5x4 periodicity

Good agreement between photoemission data and first-principles calculations

Surface features observed within 1 eV below the valence band maximum

Abstract

Thin Ge layers deposited on Si(105) form a stable single-domain film structure with large terraces and rebonded-step surface termination, thus realizing an extended and ordered Ge/Si planar hetero-junction. At the coverage of four Ge monolayers angle-resolved photoemission spectroscopy reveals the presence of two-dimensional surface and film bands displaying energy-momentum dispersion compatible with the 5x4 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.