Abstract
We studied the optical-second-harmonic generation from thin films, using a combination of frequency-, rotational-, angular-, and film-thickness-dependent measurements. We present a method to resolve the phase of by exploiting the interference between the overlayer contribution and the anisotropic Si(111) substrate contributions. We find a strong and sharp resonance at 2ħω=3.60 eV. The linewidth is found to be surprisingly small as compared to linear ellipsometry and third-harmonic-generation experiments. The intensity as a function of film thickness agrees with a model considering interference effects between equal second-harmonic contributions from the inner /Si interface and the outer surface. The possibility of nonlocal bulk contributions is discussed.
- Received 22 July 1992
DOI:https://doi.org/10.1103/PhysRevB.48.2759
©1993 American Physical Society