The Current Conduction Characteristics Of GaAs Non-Linear Photoconductive Switch

GaAs Photoconductive semiconductor switches (PCSS) has been taken an important part in the pulse power technology for the virtue of no trigger jitter, switching speed, a small parasitic inductance and capacitors, high-repetition-rate, simple structure and high voltage, etc. It has broad application prospects. But associated with the non-linear work mode, the current filaments and the field, which locked for tens of microseconds, cause great damage to the PCSS, and has greatly affected to the re-used output and the life of the switch.Thorough the experiments, the paper analyze the impact of the electrode gap and the energy of the trigger laser to the output of the switch. Indicate that the transfer of electronic effect is the main factor of the non-linear work mode. The carrier concentration must come to a particular scope, which is the necessary condition for the formation of the high-field domain. Use the EL2 level defect theory to explain the peculiar output waveform in the vicinity of the threshold value. Propose a streamer mode based on the gas discharge theory and the theory of optically activated charge domain. Calculate the field, in which the streamer propagates, by Poisson equation. Get conclusion that the photon plays an important role in the propagation of the streamer, the Franz-Keldysh (F-K) effect and the Burstein-Moss (B-M) effect is the main factor that affect the current filaments speed. Analyze the output current of the photoconductive switch. Explain the rapid increase character of output current, and the lock-on current. In the role of the high-bias electric field, the path that the current filaments come though the switch is selective. It is the Filamentary currents caused PCSS's the breakdown, while the thermal breakdown eventually led to the switch failure. There are two kinds of breakdown stages, the complete breakdown and incomplete breakdown. The incomplete breakdown is due to the bias voltage is not large enough and the avalanche multiplication is not very severe, the new generated carrier can not make sufficient number of lattice scattering, to break the chemical bonds in GaAs, and not completely destroyed the structure of switch material. Design a multi-filaments discharge experimental method, which is induced by coupled multi-fiber.