Electron trapping and paramagnetic defect density measurements in hydrogenated amorphous silicon

Electron deep-trapping mobility-lifetime (μτ) products were measured in a series of hydrogenated amorphous silicon (a-Si:H) specimens using the transient photocurrent charge-collection technique. A logarithmic dependence of the resulting μτ estimate upon the collection time was observed. The correlation of μτ with independent electron spin resonance spectroscopy determinations of the D⁰ defect density N_s was studied. The data are roughly distributed as μτ ∝ N_s^-1 for specimens prepared from pure silane at varying deposition temperatures. The correlation supports the proposal of Street that the predominant deep trap for electrons is the D⁰ defect.