Carrier avalanche multiplication quenching and pulse width control of nonlinear gallium arsenide photoconductivity switches*

    Non-linear Gallium arsenide photoconductivity semiconductor switch (GaAs PCSS) can generate high voltage and strong current electrical pulses with low light triggering at the order of micro joule. Due to the Lock-on effect of the GaAs PCSS, the output pulse width is usually on the order of hundreds nanoseconds or even tens of microseconds. This severely limits the application of nonlinear GaAs PCSS. This paper presents the output pulse width modulation of non-linear GaAs PCSS through the dual regulation of energy-storage capacitance and current-limiting resistance. When triggered by a pulse laser with a width of 10 ns and single pulse energy of 200 μJ, the switch can output the minimum pulse width of the 6.3 ns and the maximum pulse width of 196 ns. Since the energy provided by the energy-storage capacitance cannot maintain the Lock-on electric field, so a carrier quenching phenomenon occurs, and the output electrical pulse width is reduce. In the meantime, combined with the theoretical analysis of Photon-Activated Charge Domain (PACD), the electric field intensity of non-linear GaAs PCSS is less than the threshold electric field of PACD, and the switch will be turned off quickly, so that different pulse width can be output.