12-15 July 2011
Saint George Hotel
Africa/Johannesburg timezone
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Conductivity crossover in hot filament CVD grown nano-crystalline diamond films doped with nitrogen.

Presented by Mr. George CHIMOWA on 13 Jul 2011 from 11:15 to 11:30
Type: Oral Presentation
Session: CMPMS2
Track: Track A - Condensed Matter Physics and Material Science


<p>We report on the synthesis and electrical characterization of nano-crystalline diamond films grown by hot filament chemical vapor deposition. Low temperature magnetoresistance measurements have shown a crossover in conductivity from hopping, activated to semi-metallic conduction as the nitrogen level in the CVD chamber is increased from 10% - 15%, 20% to 22% respectively. Raman spectroscopy studies and SEM micrograph indicate a change in morphology with deposition parameters such as pressure, temperature and gas chemistry while AFM micrograph suggests a columnar growth process. In the semi-metallic regime the conduction is characterized by anisotropic 3D weak localization mechanism with a weak temperature dependence of the dephasing time (D) approximately (D)  T-0.7. Such behavior has been reported in Superlattice structures. Understanding of the transport properties in nano-crystalline diamond films is a perquisite for the application of diamond films in nano-electronics for fast switching and field emission devices.

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Room: Acro1

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