Photocarrier transport in undoped microcrystalline silicon studied by the modulated photocurrent technique.

A detailed investigation of photocarrier transport and localized states in undoped hydrogenated microcrystalline silicon (μc-Si:H) has been performed using the modulated photocurrent (MPC) technique. The MPC-derived drift mobility shows a systematic variation with crystalline grain size and volume fraction, as well as a distinct anisotropy. The physical implications of these observations are discussed in accordance with models that consider connectivity of crystalline grains and geometry of individual grains. The frequency spectra of MPC mobility and their dependence on excitation intensity are also analyzed in comparison with those observed for hydrogenated amorphous silicon (a-Si:H), leading to a common property of localized states that can explain the experimental results for these materials. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]