The investigation of custom grown vertical zone melt semi-insulating bulk gallium arsenide as a radiation spectrometer

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · IEEE Transactions on Nuclear Science

DOI:https://doi.org/10.1109/23.507073· OSTI ID:277692

McGregor, D S; Antolak, A J ^[1]; Chui, H C ^[2]

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1. Sandia National Labs., Livermore, CA (United States)
2. Sandia National Labs., Albuquerque, NM (United States); and others

Vertical zone melt (VZM) bulk GaAs boules have been zone refined (ZR) and zone leveled (ZL) to reduce EL2 deep donor levels and impurity concentrations with the intent of improving properties for gamma ray detectors. Zr and Zl GaAs boules had background impurity levels and deep donor EL2 concentrations near or below detectable limits. The crystal mosaic of the material at locations near the seed end was slightly superior to commercial liquid encapsulated Czochralski (LEC) material, and nearly equivalent to commercial vertical gradient freeze (VGF) material. The crystal mosaic in ZL material degraded towards the tail end. The homogeneity of the electrical properties for the ZL and ZR VZM material was inferior compared to commercially available bulk GaAs material. Post growth annealing may help to homogenize some electrical properties of the material. The charge collection efficiency of the ZR GaAs detectors was only 30% maximum, and only 25% maximum for the ZL GaAs detectors. Resulting gamma ray spectra was poor from detectors fabricated with the ZL or ZR VZM material. Detectors fabricated from material that was both ZR and ZL did not demonstrate gamma ray resolution, and operated mainly as counters. The poor spectroscopic performance is presently attributed to the inhomogeneity of the electrical properties of the ZR and ZL GaAs materials. Comparisons are made with detectors fabricated from VGF SI bulk GaAs.

• OSTI ID: 277692
• Report Number(s): CONF-951073--
• Journal Information: IEEE Transactions on Nuclear Science, Journal Name: IEEE Transactions on Nuclear Science Journal Issue: 3Pt2 Vol. 43; ISSN 0018-9499; ISSN IETNAE
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
BULK SEMICONDUCTOR DETECTORS
COMPARATIVE EVALUATIONS
ELECTRICAL PROPERTIES
GALLIUM ARSENIDES
GAMMA DETECTION
GAMMA SPECTROMETERS
MATERIALS
PERFORMANCE
ZONE MELTING
ZONE REFINING