Influence of ion energy and substrate temperature on the optical and electronic properties of tetrahedral amorphous carbon (ta-C) films

Chhowalla, M, Robertson, J, Chen, CW, Silva, SRP, Davis, CA, Amaratunga, GAJ and Milne, WI (1997) Influence of ion energy and substrate temperature on the optical and electronic properties of tetrahedral amorphous carbon (ta-C) films JOURNAL OF APPLIED PHYSICS, 81 (1). 139 - 145. ISSN 0021-8979

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Abstract

The properties of amorphous carbon ~a-C! deposited using a filtered cathodic vacuum arc as a function of the ion energy and substrate temperature are reported. The sp3 fraction was found to strongly depend on the ion energy, giving a highly sp3 bonded a-C denoted as tetrahedral amorphous carbon ~ta-C! at ion energies around 100 eV. The optical band gap was found to follow similar trends to other diamondlike carbon films, varying almost linearly with sp2 fraction. The dependence of the electronic properties are discussed in terms of models of the electronic structure of a-C. The structure of ta-C was also strongly dependent on the deposition temperature, changing sharply to sp2 above a transition temperature, T1, of '200 °C. Furthermore, T1 was found to decrease with increasing ion energy. Most film properties, such as compressive stress and plasmon energy, were correlated to the sp3 fraction. However, the optical and electrical properties were found to undergo a more gradual transition with the deposition temperature which we attribute to the medium range order of sp2 sites. We attribute the variation in film properties with the deposition temperature to diffusion of interstitials to the surface above T1 due to thermal activation, leading to the relaxation of density in context of a growth model.

Item Type:	Article
Uncontrolled Keywords:	Science & Technology, Physical Sciences, Physics, Applied, Physics, DIAMOND-LIKE CARBON, A-C, SUBPLANTATION MODEL, COMPRESSIVE-STRESS, MOLECULAR-DYNAMICS, DEPOSITION, SILICON, GROWTH, ARC, IMPLANTATION
Related URLs:	Author
Divisions:	Faculty of Engineering and Physical Sciences > Electronic Engineering > Advanced Technology Institute > Nano-Electronics Centre
Depositing User:	Melanie Hughes
Date Deposited:	08 Oct 2010 15:35
Last Modified:	23 Sep 2013 18:38
URI:	http://epubs.surrey.ac.uk/id/eprint/2442

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