Structural Memory Model of Slow Defect Relaxation in Hydrogenated Amorphous Silicon

Structural memory is a model of the timescales and energetics of defect structural relaxation after carrier capture in an amorphous solid. In this paper, an outline of the theory is given and the energetics of relaxation and the various pathways for carrier re-emission are discussed in detail. In the model, bond angle relaxation is rapid (picoseconds) after carrier capture as it is at mostcrystalline defects. However, complete structural relaxation at higher neighbors is far slower and can be reversible under some conditions. The structural memory model provides a physically reasonable, quantitative, explanation of recent anomalous transient capacitance data in hydrogenated amorphous silicon.