8.1.1.2 Differential reflection

This chapter discusses optical properties of surfaces. The optical properties of clean solid surfaces have been studied by means of a variety of experimental techniques, including ellipsometry, absorption and reflection of light, photoconductivity, photovoltage spectroscopy, photoluminescence, photothermal displacement spectroscopy and second-harmonic generation. This chapter particularly discusses differential reflection. Differential reflection (DR) measures the change in reflectance induced by a surface modification, for instance chemisorption of molecules onto a clean surface. The reflectance change is related to the optical properties of both the starting and the modified surfaces. DR, both in external and internal configurations, has been applied to study the surface properties of covalent (Si, Ge) as well as III-V semiconductors (GaAs, GaP, InP).