Figure 6.
(a) Schematic of conduction band, valence band and a donor and acceptor like trap. The downward transitions have coefficients kn,p, some of which are amplified by Coulomb attraction between charge carrier and charge state of the trap. These are the transitions between free electrons and positively charged (donor-like) trap and between free holes and a negatively charged (acceptor-like) trap. (b) Capture coefficients kn,p including the effect of Coulomb attraction as a function of the position of a singly charged (acceptor-like or donor-like) trap whose position may change between conduction and valence band edge as indicated in (a). The capture coefficients are calculated using semi-classical multiphonon theory and trap-depth and charge state dependent Huang-Rhys factors as discussed in [86–88]. (Online version in colour.)