Cathodoluminescence and Hall-effect measurements in sulfur-doped chemical-vapor-deposited diamond

Dominant n-type conductivity in sulfur-doped chemical-vapor-deposited diamond is observed by Hall-effect measurement. The activation energy is estimated at 0.5-0.75 eV above 600 K. Below 600 K, the carrier concentration deviates from the activation energy, and Hall mobility decreases in comparison with that above 600 K. It is considered that hopping conduction takes place. By cathodoluminescence measurement, free-exciton recombination radiation is observed in spite of a very high sulfur doping level of 2.5% during deposition, where boron is not detected by secondary ion mass spectroscopy. Therefore, the n-type conductivity of sulfur-doped diamond is caused by a sulfur-related mechanism. (C) 2003 American Institute of Physics.