Energy levels and charge distributions of nonideal dangling and floating bonds in amorphous Si

Defect-state wave functions and energies are calculated for numerous configurations of nonideal dangling and floating bonds in a-Si with use of Bethe-lattice-terminated clusters and a tight-binding approach. The energy eigenvalue for the dangling bond is highly dependent on deviations from ideality while the wave-function amplitudes are much less so. Exactly the opposite holds for the floating bond. The experimental consequences of these calculations are discussed.