A relation between the binding energy and the band-gap energy in semiconductors of diamond or zinc-blende structure

Abstract

From an empirical calculation of bond energy, of semiconductors of diamond and zinc-blende structures, and of some wurtzite-type, it is revealed that between the gap energy E g and single-bond energy E s there exists a linear correlation which, for the different series of binary semiconductors of tetrahedral coordination taken into consideration here, can be expressed by a relation of the type : E g = a( E s − b) where a and b are characteristic constants of the series A iv A iv , A iii B v ,A ii B vi . The correlation found for the said semiconductors are not valid for the compounds A i B vii of zinc-blende type structure and for the two oxides ZnO, CdO of wurtzite-type structure. This fact is attributed to the almost completely ionic character of the bond in these compounds, because of which the localization of the electrons along the valence bonds is negligible.