The temporal development of electrical breakdown in laser triggered GaAs-switches
- Old Dominion Univ., Norfolk, VA (United States). Physical Electronics Research Inst.
Photoconductive GaAs-switches are used to switch electrical power in excess of one Megawatt and on a time scale of nanoseconds and less. When operated at very high applied fields and triggered with low energy lasers, the electrical breakdown leads to the development of current filaments with a forward voltage which corresponds to an average electric field of several kV/cm. The temporal development of the electrical breakdown in semi-insulating GaAs has been studied by means of electrical and optical diagnostics, particularly with a recently developed electro-absorption technique. The observed phenomena are analogous to glow-to-arc transitions in electrical discharges in electronegative gases, where the attachment coefficient is a rapidly increasing function of the electric field. Semi-insulating GaAs is characterized by the presence of a large concentration of electron and hole traps, with trapping cross-sections which in certain cases increase with the electric field intensity. As field enhanced electron attachment in gas discharges, field enhanced trapping in semi-insulating semiconductors can lead to the formation of high field domains. Impact ionization of deep centers in these domains is assumed to cause the generation of an electron-hole plasma. This plasma serves as the nucleus for streamers which develop into a current channel and bridge the gap between the contacts. The continuity of the current flow at forward electric fields of kV/cm is assumed to be due to double injection.
- OSTI ID:
- 51764
- Report Number(s):
- CONF-940604--; ISBN 0-7803-2006-9
- Country of Publication:
- United States
- Language:
- English
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