Effect of under- and overcoordination on the electronic structure of amorphous silicon

Abstract
A new way is proposed to confirm, or not confirm, the simultaneous presence of both dangling and floating bonds (under- and overcoordinated Si atoms) in amorphous Si. It is based on the consequences of interaction effects among the different types of defects. While interference effects among dangling bonds only broaden the peak centered at the energy of the isolated defect level, floating bonds interact among themselves and with dangling bonds producing new states that are spread within the whole mobility gap. An experimental search for these states is proposed.