Monte Carlo Simulation of Dember Effect in n-InAs under Subpicosecond Laser Pulse Excitation

Monte Carlo method is used to simulate photo-Dember effect and generation of electromagnetic terahertz pulses in n-InAs excited by femtosecond laser radiation. Dynamics of electric field and transport of carriers were considered self-consistently. It is shown that, under excitation of semiconductor by laser pulses with photon energies < 1.1 eV, the Dember photovoltage reaches a peak value (it can be in tens times larger than the typical Dember photo-electromotive force at stationary illumination) through 50–100 fs after excitation and then fades while oscillating with plasma frequency. Excitation of semiconductor by radiation with a greater photon energy (> 1.1 eV) results in inter-valley transfer of photoelectrons and the photovoltage to decrease.