Point Defects in Non-Metals: The Role of Structure

Abstract

The aim of this volume is to review the properties of defects in non-metals, particularly their structural properties. Apart from impurities, such defects are, of course, only the atoms of the solid arranged in a different way (and sometimes also in different states of ionisation). In general, therefore we might expect to see the differences between different classes of solids (metals, ionic solids, covalent semiconductors, etc.) reflected in the properties of the defects in these solids. Often we can, though it is the manifestations of the defects which frequently provide the most obvious differentiation. This is imply another way of saying that one often studies the properties of the defects through their effect on the most characteristic properties of the solid; e.g. in semiconductors through their effect on electrical properties, in wide-gap ionic materials through their effect on optical properties, and so on. Such differentiation is not particularly fundamental. Indeed when we look at lattice defects at the more fundamental level of atomic arrangement, electronic states, energy levels and so forth such differences between one class of substances and another may well disappear.