Photoelectron emission from heavily B-doped homoepitaxial diamond films

We discuss the energy band structure near the valence band maximum based on photoemission yield spectroscopy experiments using a hydrogen-terminated heavily boron-doped homoepitaxial diamond film with concentration of 3 x 10(20) cm(-3). The experimental results showed a metallic photoemission behavior with a negative electron affinity surface. Based on the fitting as metallic photoemission behavior with a Fowler plot, the Fermi level should be at 5.35 eV below the conduction band minimum, which means that the Fermi level lies at 0.12 eV (5.47-5.35 eV) above the valence band maximum. Thus the film shows metallic conduction by the Mott transition, but not as degenerate semiconductor. (C) 2008 Elsevier B.V. All rights reserved.