We have fabricated a new class of diode from two different polytypes of boron carbide. Diodes were fabricated by chemical vapour deposition from two different isomers of closo-dicarbadodecaborane: closo-1,2-dicarbadodecaborane (orthocarborane, C 2 B 10 H 12) and closo-1,7-dicarbadodecaborane (metacarborane, C 2 B 10 H 12), differing only by the carbon placement within the icosahedral cage. We find that the electronic structure (molecular orbitals) of these two isomer molecules and the resulting decomposition reflect the tendency of metacarborane to form an n-type semiconductor while orthocarborane is an effective source compound for a slightly p-type semiconducting boron carbide. The diodes of this novel class are effective solid state neutron detectors, and have a number of unique applications.

No abstract

Real-time solid-state neutron detectors have been fabricated from semiconducting boron-carbon alloys, deposited by plasma-enhanced chemical vapor deposition. Single neutrons were detected and signals induced by gamma rays were determined to be insignificant. The source gas closo-1,2-dicarbadodecaborane ͑ortho-carborane͒ was used to fabricate the boron-carbon alloys with only the natural isotopic abundance of 10 B. Devices made of thicker boron-carbon alloy layers enriched in 10 B could lead to increased detection efficiency and active diodes could use the inherent micron scale spatial resolution, increasing the range of possible applications.

Adenwalla, Shireen; Welsch, P.; Harken, A.; Brand, Jennifer I.; Sezer, A.; and Robertson, Brian W., "Boron carbide/n-silicon carbide heterojunction diodes" (2001). Faculty Publications from Nebraska Center for Materials and Nanoscience. 85.

No abstract