Electronic structure of highly mismatched semiconductor alloys

We consider a new class of semiconductor alloys in which metallic atoms are partially replaced by highly electronegative atoms. The electronegative atoms introduce localized levels close to the conduction band edge of the host semiconductor matrix. Interaction of the levels with the extended states is described in terms of a band anticrossing. The interaction leads to a massive modification of the electronic structure splitting the conduction band into two highly nonparabolic subbands. The band anticrossing model accounts very well for recent experimental results obtained on several highly mismatched alloy systems including, GaInNAs, GaNP, ZnSTe and ZnSeTe alloys.