Pulsewidth Control of Nonlinear GaAs Photoconductive Semiconductor Switch

Abstract

The nonlinear gallium arsenide photoconductivity semiconductor switch (GaAs PCSS) can generate high-voltage and strong current electrical pulses with low light triggering at the order of microjoule. Due to the lock-on effect of the GaAs PCSS, the output pulsewidth is usually on the order of hundreds of nanoseconds or even tens of microseconds. This severely limits the application of nonlinear GaAs PCSS. This article presents the output pulsewidth modulation of nonlinear 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 a single pulse energy of 200 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{J}$ </tex-math></inline-formula> , the switch can output the minimum pulsewidth of 6.3 ns and the maximum pulsewidth of 196 ns. In the meantime, combined with the theoretical analysis of photon-activated charge domain (PACD), the electric field intensity of nonlinear GaAs PCSS is less than the threshold electric field of PACD, and the switch will be turned off quickly so that different pulsewidths can be output. The experimental results indicate that adding different current-limiting resistances and energy-storage capacitance in the circuit can control the electric field intensity so that different pulsewidths can be output.