Research On Characteristics And Physical Mechanism Of GaAs Photoconductive Semiconductor Switch Triggered By Composite Light

High-voltage and ultra-fast(nanosecond,subnanosecond,picosecond)electric pulses are urgently needed to be solved in many high-tech fields(communications,radar,electronic countermeasures,electromagnetic weapons,inertial confinement nuclear fusion,high-current ignition,accelerators,and THz technologies).The key issues belong to major national needs and are also the focus of research in the international scientific community.Photoconductive semiconductor switch combine ultrafast optics with semiconductor device technology to solve this problem.The traditional photoconductive semiconductor switch is composed of an optoelectronic semiconductor chip combined with an ultrafast pulsed laser,and has been applied in high-tech fields such as international frontier scientific research and national defense science and technology.However,as the trigger light source for photoconductive semiconductor switch,various solid state pulsed lasers are not only bulky and expensive,but are not suitable for practical outfield applications including on-board operation.Semiconductor lasers have single pulses despite their advantages of small size and moderate price,the energy is only in the micro-focus range,and the pulse width is large,so it is not easy to multi-channel precision synthesizer and other factors,which greatly limits the wide application of photoconductive semiconductor switch.Starting from the experiment,we use the radiation emitted by the spark gap discharge as a light source to trigger the GaAs photoconductor semiconductor switch.First,we measured and analyzed the characteristics of the light source from the time domain waveforms,spectral distribution,and spatial energy distribution.From the measurements and calculations we can obtain that the light energy of this light source is proportional to the distance between the two electrodes.It was found that the length of the wire between the spark gap switch and the GaAs photoconductor semiconductor switch had no effect on the pulse width of the light pulse waveform,but only a slight change in the amplitude.We have developed a new combination switch of spark gap and GaAs photoconductive semiconductor chip.The composite wavelength pulse light emitted by the spark gap discharge is used as the trigger light source of the gallium arsenide photoconductive chip,so that the switch can realize several tens of kilovolts and nanoseconds.In this paper,the spark gap discharge radiant light triggers the photoconductive semiconductor switch to successfully enter the linear and nonlinear operating modes.It is calculated that the doubling rate of the GaAs photoconductive semiconductor switch in the non-linear operation mode is about 54 times.Triggering GaAs photoconductor semiconductor switch with composite light produces a photoconductive effect.The intrinsic absorption limit of a GaAs photoconductive semiconductor switch is 0.875 ?m,and all the wavelengths of the discharge energy of the spark gap discharge are within the absorption limit.Therefore,the GaAs photoconductive semiconductor switch absorbs the spark discharge radiation mainly by intrinsic absorption.