Electric conductivity of boron nitride thin films enhanced by in situ doping of zinc

The authors demonstrate that the electric conductivities of cubic and hexagonal boron nitride (c-BN and h-BN) thin films increased markedly by the in situ doping of zinc. The doped films were electrically semiconducting, and conductivities at room temperature increased from 10(-8) to 10(-2) Omega(-1) cm(-1) with increasing zinc concentration from 400 to 20 000 ppm. Activation energies for electric conduction (E-c) of c-BN decreased from 0.3 to 0.1 eV with increasing zinc concentration, suggesting feasible shallow-level doping. On the other hand, h-BN thin films showed approximately 0.1 eV higher E-c than those of c-BN's, due to the formation of defective B-B bonds. (c) 2006 American Institute of Physics.