Papers by Keyword: Variable Range Hopping Conductivity

Abstract: Graphitic-diamond heterostructure may be very helpful not only for high frequency or power devices but also for new generation of electronic devices like single electron transistors or quantum computers operated at room temperature. The goal of our work was a formation of nanothin amorphous carbon or graphite layers with sp3 or sp2 hybridization inside the nitrogen doped synthetic monocristalline diamond by high dose hydrogen implantation. It was found that there is a “critical” dose of 50 keV hydrogen molecular ions equal to 4x1016 cm-2 above which an irreversible drop of the sheet resistivity in implanted layer occurs after annealing above 1000 oC. The nature of this conductivity was investigated and it was shown that variable range hopping mechanism of 3D conductivity dominates in investigated temperature interval. Four times higher value for the onset of this conductivity in comparison with “critical” dose for graphitization is explained by interaction of implantation induced defects with nitrogen atoms and surface defects.

Abstract: This paper presents an analysis of the electrical characteristics of the amorphous silicon carbide films deposited on the SiO2/Si substrate. Aspects of RF plasma treatment on electrical and structural characteristics of a-SiC film are discussed. It is demonstrated that the dominant mechanism of current transport in the a-SiC thin film is determined by variable-range hopping conductivity at the Fermi level. Studies of the a-SiC film at temperatures from 300 K to 600 K also indicate that silicon carbide is a perspective material for fabrication of temperature sensor.

Abstract: Basing on the study of the transport in disordered carbon nanomaterials we argue that the correct description of the magnetoresistance can be obtained in a spin polarization theory, which processes separately the spin and orbital degrees of freedom in hoping conductivity in magnetic field. It is found that the polarization of the spin part of the electron wave function controls the probabilities of the hops between the single and double occupied localized states and, moreover, the spin polarization process can be treated as in the paramagnet with spin S=1/2. The experimental checking of the universal magnetoresistance scaling expected in the spin polarization model is provided.