Hydrogen-induced metastable changes in the electrical conductivity of microcrystalline silicon

The temperature dependence of the electrical dark conductivity sigma(D) of microcrystalline silicon was measured. Rapid thermal cooling resulted in an increase of sigma(D) by two orders of magnitude below 300 K. This frozen-in state is metastable: annealing and a slow cool restores the temperature dependence of the relaxed state. The time and temperature dependence of the relaxation Of sigma(D) reveals that two processes are competing. At short times sigma(D) increases while at long times sigma(D) decreases. The latter process is due to the dissociation of bondcenter H complexes.