Hopping conduction in semiconducting diamond

The electronic conductivity of synthetic boron-doped diamonds is studied in the temperature range 12-1300^∘{}K. It is shown that in the low-temperature range (below 150-100^∘{}K) the results are best interpreted in terms of variable-range hopping. An attempt to evaluate quantitatively the parameters which characterize this hopping mechanism is made using the boron concentration and the degree of compensation determined from the variation of conductivity in the high-temperature range, coupled with optical-absorption measurements. The effect of irradiation with energetic electrons, which introduced new compensating centers, is investigated and can also be explained in terms of the theory for the hopping mechanism.