The perspectives of high-rate low frequency a-Si:H films deposition:: Solar cell application and stability control

The perspectives for solar cell application of structural inhomogeneous a-Si:H films deposited at high growth rates (similar to 10-20 Angstrom/s) from 100% SiH4 in low frequency (LF) 55kHz glow discharge plasma have been investigated. In this case the influence of structural inhomogeneity on dark de and photoconductivities and light-induced defect generation kinetics (Staebler-Wronski effect, SWE) in a-Si:H films have been studied. The microstructure of films was investigated by IR spectroscopy analysis. Microstructural parameter R=[SiH2]/([SiH]+[SiH2]), was used for the quantitative characterization of structural inhomogeneity in the material bulk. It was found that Fermi level position is fixed by deep defect states and does not depend on microstructure parameter R. The comparative analysis of photoconductivity modeling and ESR measurements have shown that recombination in a-Si:H films is controlled by neutral dangling bonds and doesn't depend on parameter R. Meanwhile it was found that the kinetics of light-induced defect generation was controlled by SiH2 or clustered SiH groups content. Thus, the above results allow to perform an independent control of stability and electronic properties of a-Si:H films deposited in LF glow discharge plasma.