Electric polarization of electron-hole pairs in organic semiconductors induced by picosecond pulses of an electromagnetic wave: Consideration of small-molecule semiconductors with a negligibly small concentration of traps

摘要

Non-stationary conductivity of an organic semiconductor is discussed for the conditions of the time-resolved pump-probe experiments, in which electrons and holes are produced by the pump femtosecond laser pulse followed by the action of the terahertz (THz) probe pulse with duration of the order of 1 ps. The developed diffusion model is applicable to small-molecule semiconductors without traps. The time dependence of conductivity due to polarization of electron-holes pairs by the electric field of the THz pulse is found as a function of the sum of the electron-hole mobilities and delay time between the pump and probe pulses.