Role of Defects, Impurities and Deviations from the Stoichiometry in the Optoelectronic Properties of Semiconductors

Abstract

Impurities have a severe influence on the optoelectronic properties of elemental and compound semiconductors, behaving, respectively, as dopants and carrier recombination centres as a function of their electronic structure. In turn, point and extended defects (dislocations, stacking faults and precipitates) behave as deep level and carrier recombination centres. The physical aspect of their behaviour is presented in detail in the first part of this chapter, whereas the chemical aspects of impurity removal processes are discussed in the second part, with special attention to the chemistry of metallic impurity gettering at oxide precipitates in silicon.