Abstract
The hydrogen collision model of light-induced metastability in hydrogenated amorphous silicon is described in detail. Recombination of photogenerated carriers excites mobile H from Si-H bonds, leaving threefold-coordinated Si dangling-bond defects. When two mobile H atoms collide and associate in a metastable two-H complex, the two dangling bonds from which H was emitted also become metastable. The proposed microscopic mechanism is consistent with electron-spin-resonance experiments. Comprehensive rate equations for the dangling-bond and mobile-H densities are presented; these equations include light-induced creation and annealing. Important regimes are solved analytically and numerically. The model provides explanations for both the time dependence of the rise of defect density during continuous illumination and the time-dependence during intense laser-pulse illumination. Other consequences and predictions of the H collision model are described.
- Received 16 March 1998
DOI:https://doi.org/10.1103/PhysRevB.59.5498
©1999 American Physical Society