Hopping conduction via the excited states of boron in p-type diamond

We report the first observation of the three types of conduction in boron-d oped homoepitaxial diamond. The first is the conduction in the valence band . The second is hopping conduction via excited states of the impurity boron , which is located 0.06 eV above the valence band. The third is the conduct ion in excited state of the impurity, and this state merges into the impuri ty band when the impurity concentration is increased. The impurity band is located 0.05 eV above the valence band. These three conduction mechanisms p roduce the activation energies of epsilon(1), epsilon(2) and epsilon(3), re spectively. (C) 2000 Elsevier Science S.A. All rights reserved.