Microscopic structure of defects in microcrystalline silicon

Abstract

Electron spin resonance (ESR) on paramagnetic defects in hydrogenated microcrystalline silicon (μc-Si:H) has been studied to investigate its microscopic structure. From the anisotropy of preferentially oriented sample along 〈1 1 0〉 we suggest that the fine structure and its angular dependence arise from the grain boundary having 〈1 1 1〉 axial symmetry with g-tensors of g ‖ ∼2.0022 and g ⊥ ∼2.0078 such as the Pb center. A simulation study indicates the presence of isotropic components arising from grain boundary defects on randomly oriented crystallites and dangling bonds in the amorphous structure. Thermal desorption of hydrogen from μc-Si:H was correlated with the isochronal annealing of the ESR spectra.