Conductivity crossover in nano-crystalline diamond films: Realization of a disordered superlattice-like structure
Nano-Scale Transport Physics Laboratory, School of Physics and DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand - Private Bag 3, WITS 2050, Johannesburg, South Africa
Received: 24 April 2012
Accepted: 25 June 2012
We present the electrical transport characteristics of a batch of nano-crystalline diamond films of varying nitrogen concentrations and explain the conduction mechanism by the disordered quasi-superlattice model applied to semiconductor heterostructures. Synthesized by the hot-filament chemical-vapour deposition technique, the degree of structural disorder in the films, confirmed from Raman spectroscopy, is found to be controllable, resulting in the transition of conduction mechanism from localized and activated to the metallic conduction regime. Hence through high-field magneto-resistance measurements at low temperatures we firmly establish a conductivity crossover from hopping to 3D weak localization. The long electronic dephasing time and its weak temperature dependence suggest the possibility for diamond-based high-speed device applications.
PACS: 73.43.Qt – Magnetoresistance / 73.20.Fz – Weak or Anderson localization
© EPLA, 2012