Light Scattering in Solids 1

Book excerpt: This book is devoted to the problem of inelastic light scattering in semiconductors, i.e., to processes in which a photon impinges upon a serniconductor, creating or anihilating one or several quasi-particles, and then emerges with an energy somewhat different from that of the incident photon. In light scattering spectroscopy the incident photons are monochromatic; one measures the energy distribution of the scat tered photons with a spectrometer. Because of its monochromaticity, power, and collimation, lasers are ideal sources for light scattering spectroscopy. Consequently, developments in the field of light scattering have followed, in recent years, the developments in laser technology. The scattering efficiencies are usually weak and thus light scattering spectroscopy requires sophisticated double and tripie monochromators with high stray light rejection ratio. Both, powerful lasers and good monochromators are specially important for studying the scattering of light to which the sampies of interest are opaque, as is the case in most semiconductors. This explains why these materials are relatively late corners to the field of light scattering. In spite of these difficulties, the field of light scattcring in semi conductors has experienced a boom in recent years, and reached a certain degree of maturity. Because of space limitations, the editor was faced with the necessity of making a choice in the subjects to be included. In spite of the natural bias towards his own research interests he hopes to have gathered a number of articles representative of present-day research in the field.