Subnanosecond photoconductive switching in GaAs

Conference · Mon Jan 01 00:00:00 EST 1990

DOI:https://doi.org/10.1109/PPC.1989.767630· OSTI ID:6943727

Druce, R L; Pocha, M D; Griffin, K L

We are conducting research in photoconductive switching for the purpose of generating microwave pulses with amplitudes up to 50 kV. This technology has direct application to impulse radar and HPM sources. We are exploiting the very fast recombination rates of Gallium Arsenide (GaAs) to explore the potential of GaAs as an on-off switch when operating in the linear mode (the linear mode is defined such that one carrier pair is generated for each photon absorbed). In addition, we are exploring the potential of GaAs to act as a closing switch in avalanche'' mode at high fields. We have observed switch closing times of less than 200 psec with 100 psec duration laser pulse and opening times of less than 400 psec with neutron irradiated GaAs at fields of tens of kV/cm. If the field is increased and the laser energy decreased, the laser can be used to trigger photoconductive switches into an avalanche'' mode of operation in which carrier multiplication occurs. This mode of operation is quite promising since the switches close in less than 1 nsec while realizing significant energy gain (ratio of electrical energy in the pulse to optical trigger energy). We are currently investigating both large are (1 sq cm) and small area (<1 sq mm) switches illuminated by GaAlAs laser diodes at 900 nm and Nd:YAG lasers at 1.06 micrometers. Preliminary results indicate that the closing time of the avalanche switches depends primarily on the material properties of the devices with closing times of 300--1300 psec at voltages of 6-35 kV. We will present experimental results for linear, lock on and avalanche mode operation of GaAs photoconductive switches and how these pulses may be applied to microwave generation. 3 refs., 11 figs.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6943727
• Report Number(s): UCRL-JC-103782; CONF-900397-3; ON: DE90011481
• Resource Relation: Conference: 1. Los Alamos symposium on ultra-wideband radar, Los Alamos, NM (USA), 5-8 Mar 1990
• Country of Publication: United States
• Language: English

Related Subjects

47 OTHER INSTRUMENTATION
42 ENGINEERING
RADAR
PULSE TECHNIQUES
SWITCHES
PHOTOCONDUCTIVITY
GALLIUM ARSENIDES
MICROWAVE EQUIPMENT
PHOTOCONDUCTIVE CELLS
SEMICONDUCTOR LASERS
ARSENIC COMPOUNDS
ARSENIDES
DIRECT ENERGY CONVERTERS
ELECTRIC CONDUCTIVITY
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
GALLIUM COMPOUNDS
LASERS
MEASURING INSTRUMENTS
PHOTOELECTRIC CELLS
PHYSICAL PROPERTIES
PNICTIDES
RANGE FINDERS
SEMICONDUCTOR DEVICES
SOLID STATE LASERS
440800* - Miscellaneous Instrumentation- (1990-)
426000 - Engineering- Components
Electron Devices &amp; Circuits- (1990-)