The hydrogen glass model

There is considerable evidence that hydrogen diffusion is the mechanism of thermal equilibration. The evidence is necessarily indirect because the hydrogen apparently does not participate directly in the defect or dopant states, but acts as a catalyst to the motion. For example, the movement of a hydrogen atom from one Si—H bond at site A to a neighboring dangling bond at site B is described by 

The viscosity of a glass is about 10 poise at the glass transition 

The phenomenon of metastability is closely related to the defect equilibrium properties. Some external excitation - illumination, charge, current flow, energetic particles, etc. - induces defects (or dopants) which are subsequently removed by annealing. The metastable 

Defects or dopants are created because the external excitation drives the defect reaction away from the initial equilibrium. The formation energy of charged defects, and therefore their equilibrium density, depends on the position of the Fermi energy according to Eqs. (6.26) and (6.27). Thus, the equilibrium defect density is 

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