Optical second harmonic generation from the Si(111)-Ga interface

Abstract The deposition of Ga on clean Si(111) has a strong effect on the optical second harmonic generation from this surface. By measuring both intensity and phase of the SHG signals, a resonant enhancement is observed around 1/3 of a monolayer for excitation with 1064 nm. This enhancement is absent for 634 nm excitation. These observations are related to the electronic structure of the Si Ga interface.