Abstract

The injected carriers due to above band gap femtosecond excitation of a biased Schottky barrier (SB), will cause a collapse of the SB-field due to a carrier sweep-out. This effect can directly be probed by a novel interface technique, optical second-harmonic generation (SHG). The reflected SHG-field $\overrightarrow{\text{E}}\left(2\omega \right)$ from a SB formed by a thin gold layer on top of GaAs(100), is related to the incident field $\overrightarrow{\text{E}}\left(\omega \right)$ and the de SB-field $\overrightarrow{\text{E}}\left(0\right)$ via interface and bulk nonlinear susceptibility of tensors. Experimentally, the two contributions can be separated, as the interface contribution is isotropic and depending on $\overrightarrow{\text{E}}\left(0\right)$, whereas the bulk contribution is anisotropic and should not depend on $\overrightarrow{\text{E}}\left(0\right)$.

© 1994 IEEE