Auger Processes in Nanosize Semiconductor Crystals

Abstract

In this chapter I discuss the role that various types of Auger processes play in the linear and nonlinear optical properties of semiconductor nanocrystals (NCs). The nanocrystal form of semiconductors was discovered by Ekimov [1], Hengeline [2], and Brus [3] independently in semiconductor doped glasses and colloidal solutions almost 20 years ago. However, rapid progress in semiconductor nanocrystal research, both in chemical synthesis and in physical understanding has been made only in the last ten years. A wide class of semiconductor materials can now be prepared in nanocrystal form including: covalent Si and Ge, III-V compounds (GaAs, GaP, InP), II-VI compounds (CdSe, CdS, ZnSe, CdTe, PbS and their alloys), and I-VII compounds (CuCl, CuBr, AgBr) (see for review Ref.[4]). Furthermore, in many cases, technology allows one to control the size (from 2 to 30 nm), shapes and surface of these nano-size semiconductor crystals (for an example, see the excellent reviews by Brus [5] and Alivisatos [6]). Realistic calculations of the nanocrystal properties allow us to make a serious analysis of experimental data (for example, see Ref.7). This together with progress in chemical synthesis has brought us to the stage of making different applications of NCs.