TY - JOUR
T1 - Spontaneous low frequency oscillation studies in gallium arsenide fast photoconductors
AU - Foulon, F.
AU - Flicstein, J.
AU - Brullot, B.
AU - Petit, P.
AU - Bergonzo, P.
AU - Rubbelynck, C.
PY - 1999/7
Y1 - 1999/7
N2 - We have investigated the influence of spontaneous low frequency oscillations (LFO, f to approximately 0.01 Hz) occurring at high electric field (>1 kV/cm) in resistive photoconductors (PCD) made from semi-insulating GaAs on the response of the PCDs under pulsed gamma-ray irradiation (E to approximately 1.2 MeV, τFWHM = 30 ns). The PCDs were fabricated using GaAs from five commercially available sources. The PCDs were irradiated with fission neutrons in order to reduce their response time down to less than 100 ps. The amplitude of the LFOs was found to be related to the carrier lifetime, and thus defect concentration in the GaAs material. It was larger for material exhibiting high carrier lifetime. Increasing the localized defect concentration, such as EL2 type defect, through GaAs irradiation with fission neutrons was found to decrease the amplitude of the LFOs. PCDs irradiated at high neutron doses (>1×1015 neutrons/cm2) showed no LFOs. It is suggested that interactions between the propagating domains and the highly defective GaAs bulk control the LFO characteristics. Gamma-ray sensitivity, in transient mode, versus bias voltage of PCDs was also found to be correlated to LFOs, showing that high-field behavior of GaAs can be used to predict the optimum operating bias of the PCDs.
AB - We have investigated the influence of spontaneous low frequency oscillations (LFO, f to approximately 0.01 Hz) occurring at high electric field (>1 kV/cm) in resistive photoconductors (PCD) made from semi-insulating GaAs on the response of the PCDs under pulsed gamma-ray irradiation (E to approximately 1.2 MeV, τFWHM = 30 ns). The PCDs were fabricated using GaAs from five commercially available sources. The PCDs were irradiated with fission neutrons in order to reduce their response time down to less than 100 ps. The amplitude of the LFOs was found to be related to the carrier lifetime, and thus defect concentration in the GaAs material. It was larger for material exhibiting high carrier lifetime. Increasing the localized defect concentration, such as EL2 type defect, through GaAs irradiation with fission neutrons was found to decrease the amplitude of the LFOs. PCDs irradiated at high neutron doses (>1×1015 neutrons/cm2) showed no LFOs. It is suggested that interactions between the propagating domains and the highly defective GaAs bulk control the LFO characteristics. Gamma-ray sensitivity, in transient mode, versus bias voltage of PCDs was also found to be correlated to LFOs, showing that high-field behavior of GaAs can be used to predict the optimum operating bias of the PCDs.
UR - http://www.scopus.com/inward/record.url?scp=0033165229&partnerID=8YFLogxK
U2 - 10.1016/S0168-9002(99)00236-3
DO - 10.1016/S0168-9002(99)00236-3
M3 - Article
AN - SCOPUS:0033165229
SN - 0168-9002
VL - 430
SP - 377
EP - 381
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
IS - 2-3
ER -