| Pulsed power technology is designd to produce high power and short electric pulse.Switches and energy storage devices used in this system to compress pulse. Therefore, how to improve the output pulse power and compression pulse width is the key to pulse power technology. The switching technology is the key link of pulse power technology, high repetition rate, all solid state and miniaturization are the main trends of the current switching technology.Based on the experimental phenomenon of nonlinear delay mode of GaAs photoconductive switch, we proposed a research method using avalanche triggering semi-insulating GaAs conduction. Using avalanche triggering semi-insulating GaAs conduction can make a GaAs photoconductive switch out of the laser limit, and achieve a new type of high-pressure avalanche tube. By optimizing the shape of the electrode, we fabricate asymmetric tip electrodes on semi-insulating GaAs materials to form experimental samples.The experiment shows that this sample can be used to apply high pressure directly ,as well as partial avalanche way to trigger conduction. The conductive semi-insulating GaAs sample can be continuously turned on as the photoconductive switch nonlinear mode and is associated with the lock -on field of the sample.On the basis of this, the paper has carried out the experimental study on the use of semi-insulating GaAs avalanche to produce high-frequency nanosecond pulse, and has completed the following work:1. The asymmetric electrodes were prepared on semi insulating GaAs samples. Based on the determination of the voltage current characteristics of the static characteristics of the sample,the pulse output characteristic of the avalanche sample was tested by using the capacitor energy storage test circuit, and a single high voltage electric pulse with pulse width of 5.5ns and 1.9kV was produced.2. Based on the volt-ampere characteristics of semi-insulating GaAs avalanche samples,a high repetition frequency operation scheme based on high-voltage AC power supply is designed, and the reverberation experiment of avalanche samples under AC power supply is carried out. The pulse width of 493.8ns, amplitude of 5.92kV, frequency of 52.2kHz and pulse width of 243ns, amplitude of 4.39kV, frequency of 40kHz pulses were generated respectively under two different power supply modes.3 .The voltammetric characteristics of GaAs body avalanche samples at high temperatures were measured. It was found that the samples exhibited high current controlled negative resistance characteristics at high temperatures. Different from the voltammetric properties at room temperature is that the high temperature sample electric locking characteristics disappear,either boost or buck process,the samples exhibit negative resistance. And the negative resistance decreases with the increase of temperature which reaches up to 2.4M? at 70?.According to the high temperature samples exhibit negative resistance characteristics, explains the formation mechanism of the current spike in HPRF mode.The semi-insulating GaAs body avalanche produces a repetitive frequency pulse, which is a new method for generating high frequency pulses, and expected to achieve dozens of kHz high voltage nanosecond pulse in the avalanche mode. The further research on the avalanche phenomenon of SI-GaAs will inject new vitality into the field of solid-state switch. |
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