Electronic properties of boron-doped {111}-oriented homoepitaxial diamond layers

p-type diamond single crystal layers were grown by Microwave Plasma-enhanced Chemical Vapor Deposition (MPCVD) on {111}-oriented Ib-type diamond substrates. The variation of the gas-phase boron-to-carbon atomic concentration ratio from 0.1 ppm to 104 ppm led to solid state incorporations of boron ranging from the 8 × 1015 cm− 3 to 3 × 1021 cm− 3. Low temperature cathodoluminescence spectra in the bandgap region are shown to yield a reliable estimate of the quality of the layers and of the neutral acceptor concentration up to the metal–insulator transition. Temperature-dependent resistivity and Hall effect measurements allow a discussion of the relevance of the various charge carrier scattering mechanisms.