Spectroscopic ellipsometry of E1-like transitions in nanometer-thickness Ge layers

Spectroscopic ellipsometry of epitaxial Ge in bulk Si(100) has been used to study the effects of strain and layer thickness on the Ge-derived E1 transitions. Although a 4-AI-Ge layer exhibits no Ge-like E1 structure, localized E1-like transitions are observed for 7-AI-Ge layers showing the E1 transition is a robust probe of the Ge-like behavior in ultrathin layers. © 1990 The American Physical Society.