  We have studied the electrical conductivity behavior of highly crystallized
undoped hydrogenated microcrystalline silicon films having different
microstructures. The dark conductivity is seen to follow Meyer Neldel rule
(MNR) in some films and anti MNR in others, which has been explained on the
basis of variation in the film microstructure and the corresponding changes in
the effective density of states distributions. A band tail transport and
statistical shift of Fermi level are used to explain the origin of MNR as well
as anti-MNR in our samples. The observation of MNR and anti MNR in electrical
transport behavior of microcrystalline silicon is discussed in terms of the
basic underlying physics of their origin and the significance of these
relationships.
