RAMAN-SPECTROSCOPY AT III-V-SEMICONDUCTOR SURFACES AND OVERLAYERS IN THE MONOLAYER REGION

The application of Raman spectroscopy is discussed for the analysis of different aspects of III-V semiconductor surfaces and interfaces, such as chemical reactivity, overlayer crystallinity and electronic band bending. The interface reactivity is studied for CdTe/InSb and for InSb/Sb. Overlayer crystallinity and electronic band bending are analyzed for Sb layers on GaAs and InP. Here submonolayer sensitivity is achieved for the ordered Sb chains in the first monolayer (ML). Furthermore, the different crystalline states of thicker overlayers are detected. The development of the electronic band bending in the substrate is monitored by Electric Field Induced Raman Scattering (EFIRS) from the substrate LO phonon for coverages from submonolayer up to about 100 ML. Considerable band bending dynamics is observed for overlayer thicknesses far beyond 1 ML.