The fluctuation-dominated and mean-field models for diffusion-controlled bimolecular recombination are compared with picosecond domain transient optical experiments on a-Si:H. Using no fitting parameters, the fluctuation-dominated model gives a good account for the optical decay times as a function of laser intensity. A lower bound for the thermalization radius of a photogenerated electron-hole pair, r0 > 12 nm, is inferred. a-Si:H ia felicitous material for exhibiting the fluctuation-dominated effects since it combines a modest electron mobility with an unexplained but large thermalization radius. However, the role of the electrostatic potential fluctuations due to the charged electrons and holes is not understood.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry