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

Abstract

Semiconductor thermal neutron detection devices based on /sup 10/B-coated high-purity GaAs films were investigated. The fundamental device consisted of high-purity /spl nu/-type epitaxial GaAs films grown onto n-type GaAs substrates. Two blocking contact adaptations were applied to the high-purity /spl nu/-type GaAs regions: 2000 /spl Aring/ thick p+GaAs blocking contacts and 200 /spl Aring/ thick Schottky blocking contacts. The /spl nu/-type GaAs active layers ranged between 1 micron and 5 microns in thickness. The device sensitive areas were 3 mm/spl times/3 mm, each of which was coated with a 1.5 mm diameter film of 98% enriched high-purity /sup 10/B. 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%.