DEFECT EQUILIBRATION AND STABILIZATION IN LOW-SPIN-DENSITY A-SI-H

Relaxation data provide evidence that thermally generated defects with spin observed in thick, undoped hydrogenated amorphous silicon (a-Si:H) films can be stabilized with alternate structural configurations. Some quenched-in metastable spins equilibrating further at a lower temperature relax and become more resistant to annealing. Although such an observation should be expected for a disordered material, it is inconsistent with predictions of two-level energy-configuration coordinate diagrams. Models employing either alternate lattice configurations for each metastable spin or different weak-bond sites for the mobile hydrogen can be used to explain this result.