High-Power Semi-Insulating GaAs Photoconductive Semiconductor Switch Employing Extrinsic Photoconductivity

Abstract

A photoconductive semiconductor switch (PCSS) with a gap of 0.018 m was fabricated from semi-insulating GaAs. Illuminated by a laser pulse with varying optical energies at a wavelength of 1064 nm, the photoconductivity tests of the PCSS were performed at different bias voltages. In nonlinear mode, by comparing the charge initially stored in the capacitors and the charge through the switch, it is found that the end of lock-on phase is not always due to the fact that the energy has been dumped from the charging system. The threshold of incident optical energy and the ON-state resistance are analyzed and calculated. The PCSS failed at a bias voltage of 32 kV because of surface flashover.Index Terms-Gallium arsenide (GaAs), high-power microwaves, photoconductive semiconductor switches (PCSSs).

A versatile high voltage nano- and sub-nanosecond pulse generator

“…As the bias voltage increased, the equivalent resistance of the switch significantly decreased, indicating an increase in switching efficiency. This can be explained by the Franz-Keldysh effect, which translates in a shift in the optical absorption edge of the PCSS toward longer wavelengths with increasing applied electric field [24,25]. Increasing the incident optical energy on the PCSS can counteract the electric field-induced decrease in the switching efficiency.…”

“…The power semiconductor switches used in ultrashort highvoltage pulse generators include a wide range of switches such as metal-oxide-semiconductor field-effect transistors (MOSFET) [14-16, 18, 19], thyristors [22] and diode opening switches [21,23]. Spark gap switches are employed in [20] while photoconductive semiconductor switches (PCSS) are used as optoelectronic switches in [24][25][26]. PCSS have two modes of operation, the linear and avalanche modes.…”