Carrier dynamics in microcrystalline silicon studied by time-resolved terahertz spectroscopy

We present results of optical pump – terahertz probe experiments applied to a set of thin film silicon samples on sapphire substrates. Structure of the films varied from amorphous to fully microcrystalline. Picosecond time scale evolution of electrical transport properties of photoexcited samples is investigated and discussed. Three different mechanisms are found to contribute to the dynamical conductivity at terahertz frequencies.