Self-biased boron-10 coated high-purity epitaxial GaAs thermal neutron detectors

Semiconductor thermal neutron detection devices based on B-10-coated high-p urity GaAs films were investigated. The fundamental device consisted of hig h-purity v-type epitaxial GaAs films grown onto n-type GaAs substrates. Two blocking contact adaptations were applied to the high-purity v-type GaAs r egions: 2000 Angstrom thick p(+) GaAs blocking contacts and 200 Angstrom th ick Schottky blocking contacts. The nu-type GaAs active layers ranged between 1 micron and 5 microns in thi ckness. The device sensitive areas were 3mm x 3mm, each of which was coated with a 1.5mm diameter film of 98% enriched high-purity B-10. The built-in potential of the-blocking contact interface was sufficient to operate the d evices, and no external voltage bias was necessary to operate the:detectors ;: Preliminary calculations on intrinsic detection efficiency indicate valu es between 1.6% and 2.6%.