The heteroisomeric diode

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, C2B10H12) and closo-1,7-dicarbadodecaborane (metacarborane, C2B10H12), 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. (letter to the editor)