Chemical Approaches to the Approximate Prediction of Band Gaps of Binary Semiconductors and Insulators

Abstract

The chemical approaches to the approximate prediction of band gaps of binary inorganic semiconductors and insulators have been briefly reviewed with special emphasis on relatively recent work. These approaches involve establishment of correlations between band gaps and various other quantities, e.g. heats of formation, bond energies and electronegatiyities, etc. It has been shown that some of these correlations provide semiquantitative means for the estimation of band gaps of several materials for which it is either too difficult or impossible to compute accurate band gaps on the basis of methods of theoretical physics. The possible theoretical foundations of some of these correlations, as examined previously, have also been presented. Some of the recently proposed correlations, e.g. between band gaps and heats of formation per equivalent, even though rough, have universal validity in that they are applicable to all types of binary inorganic compounds covering a wide range of ionicity, crystal type, and band gaps.