Metastability effects in hydrogenated microcrystalline silicon thin films investigated by the dual beam photoconductivity method

Metastability effects in microcrystalline silicon (μc-Si:H) thin films have been investigated using dark conductivity, σD, photoconductivity, σph, and sub-bandgap absorption methods. Nitrogen and inert gasses can cause reversible aging effect in conductivities but not in the sub-bandgap absorption. However, DI water and O2 gas treatment result in both reversible and nonreversible effects in conductivities as well as in the sub-bandgap absorption. Only oxygen affected the dark conductivity reversibly in amorphous silicon, a-Si:H, films, other results were unaffected from the aging and annealing processes applied.

► Microcrystalline silicon films were aged under controlled gas ambients. ► Aging were characterized by measuring the changes in dark and photoconductivity and dual beam photoconductivity method. ► Nitrogen and inert gas exposures can cause reversible aging effect. ► DI water and oxygen cause larger changes in conductivities and sub-bandgap absorption. ► The bulk of amorphous silicon film is not affected from different aging processes.