Nonlinear Studies of Surface and Interfaces of Advanced Semiconductor Materials

摘要

A growing interest has developed in the past few years regarding the role that optical second harmonic generation (SHG) can play in characterization of buried interfaces. This interest arises form the unique sensitivity of SHG to the properties of the interface itself with inherent discrimination against properties of the adjacent bulk media. In UHV studies, it has been used to monitor surface structure, adsorption and desorption of molecules, and surface melting. Much of interest during this time has been to investigate the fundamental aspects of the optical second harmonic generation to the solid/liquid interface and solid/solid junction. In previous electrochemical studies we have demonstrated the sensitivity of SHG to film growth, molecular and ionic adsorption and potential dependent effects associated with changes in surface morphology, all on single crystal and smooth polycrystalline surfaces. Our most extensive investigations have involved measuring surface order, surface electronic structure and thin film deposition in situ on crystalline metal electrodes by analysis of the rotational anisotropy in the polarized SH response. More recently we have expanded the work to study oxidation of metals and the metallization of semiconductor surfaces.