The statistics of recombination via dangling bonds in amorphous silicon

Dangling bonds are an important type of recombination centre in semiconductors such as amorphous silicon, so that an accurate analysis of their properties is of considerable value. The large positive correlation energy of the electron states associated with such dangling bonds leads to rather cumbersome and complicated forms of the exact formulae for their occupation statistics and the rate of recombination through them. In this paper it is shown that, under many conditions, a dangling bond behaves in the same way as a pair of independent ordinary electron states. The use of this two-state model, especially in conjunction with Rose’s demarcation level approximation, leads to simple formulae that are very suitable for calculations and for the analysis of experimental results.