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

Novel semiconductor thermal neutron detection devices based on ¹⁰B coated epitaxial GaAs films were investigated. Two basic structures were investigated, those being high purity n-type GaAs layers grown on n-type GaAs substrates, over which either 2000 Å thick p+ blocking contacts were grown or over which 200 Å thick Schottky blocking contacts were applied. The n-type GaAs active layers ranged between 1 micron and 5 microns in thickness. The device sensitive areas were 3 mm×3 mm, each of which was coated with a 1.5 mm diameter film of 98% enriched high purity ¹⁰B. The built-in potential of the blocking contact interface was sufficient to operate the devices, and no external voltage bias was necessary to operate the detectors. Preliminary calculations on intrinsic detection efficiency indicate values between 1.6% and 2.6%