Low‐temperature electrical conductivity of heavily boron‐doped diamond single crystals

Abstract

Abstract Single crystal diamonds 0.2–0.7 cm large doped with boron concentration 10 19 –10 20 cm –3 were grown by temperature gradient method on the seed under pressure P = 5.5 GPa, temperature T = 1650 K. Temperature dependence of electrical resistance had been measured in the range of 0.5–297 K. Boltzmann activation type of conductivity and Mott's VRH law observed in samples in the temperature ranges ∼200–297 K and ∼70–297 K respectively. The temperature rise of conductivity in the range of ∼0.5–50 K for most heavily doped crystals was proportional to T 1/2 . This rule indicates the vicinity of the electronic system to metal–insulator transition. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)