Magnetic and electrical characterization of heavily boron-doped diamond

For a heavily boron-doped diamond (BDD) film, temperature variations of the electrical conductivity σ and magnetic susceptibility χ are reported. The room temperature σ ≃143 (Ω-cm)−1 corresponds to a carrier concentration ≃103 ppm, and its temperature variation yields an activation energy Ea ≃28 meV from 140 to 300 K and Ea≃0.88 meV from 40 to 80 K. It is argued that larger boron doping leads to lower magnitudes of Ea. The χ vs. T data (1.8–350 K) fits the Curie–Weiss law, with the concentration of paramagnetic species ≃120 ppm and a diamagnetic susceptibility ≃−0.4×10−6 emu/g Oe. The results obtained from the measurements of σ and χ are discussed and compared.