CUED Publications database

Defect and disorder reduction by annealing in hydrogenated tetrahedral amorphous carbon

Conway, NMJ and Ferrari, AC and Flewitt, AJ and Robertson, J and Milne, WI and Tagliaferro, A and Beyer, W (2000) Defect and disorder reduction by annealing in hydrogenated tetrahedral amorphous carbon. Diamond and Related Materials, 9. pp. 765-770. ISSN 0925-9635

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Abstract

Hydrogenated tetrahedral amorphous carbon (ta-C:H) is a form of diamond-like carbon with a high sp3 content (>60%), grown here using a plasma beam source. Information on the behaviour of hydrogen upon annealing is obtained from effusion measurements, which show that hydrogen does not effuse significantly at temperatures less than 500 °C in films grown using methane and 700 °C in films grown using acetylene. Raman measurements show no significant structural changes at temperatures up to 300 °C. At higher temperatures, corresponding to the onset of effusion, the Raman spectra show a clustering of the sp2 phase. The density of states of ta-C:H is directly measured using scanning tunnelling spectroscopy. The measured gradients of the conduction and valence band tails increase up to 300 °C, confirming the occurrence of band tail sharpening. Examination of the photoluminescence background in the Raman spectra shows an increase in photoluminescence intensity with decreasing defect density, providing evidence that paramagnetic defects are the dominant non-radiative recombination centres in ta-C:H.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div B > Solid State Electronics and Nanoscale Science
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 11:26
Last Modified: 14 Dec 2014 12:45
DOI: 10.1016/S0925-9635(99)00271-X