Influence of dangling-bond defects on recombination ina-Si:H

Time-resolved photoinduced absorption (PIA) and steady-state photoconductivity (PC) experiments are used to study recombination processes in electron-irradiated hydrogenated amorphous silicon (a-Si:H). Defect densities measured by ESR range from 5×${10}^{15}$/${\mathrm{cm}}^3$ to ${10}^{18}$/${\mathrm{cm}}^3$. It is found that while increasing the dangling-bond density reduces the PC, the PIA decay rate increases. The results are discussed in the context of a recombination model where the defect density determines whether the carriers recombine through a fast bimolecular or a slower monomolecular process.