DC electrical properties of amorphous carbon with different bonding hybridization

Temperature dependence of dc conductivity in hydrogenated amorphous carbon (a-C:H) samples, deposited in the range of −200 to −700 V self-bias voltages, was studied above room temperature from 300 K to 650 K. Because a non-Arrhenius dependence on 1/ T was found, actual activation energy E act was de...

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Bibliographic Details
Published inJournal of non-crystalline solids Vol. 227; pp. 1087 - 1091
Main Authors Moustafa, S.H, Koós, M, Pócsik, I
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.01.1998
Subjects
Amorphous carbon
Bonding hybridization
DC electrical properties
DC electrical properties
A190
E130
Bonding hybridization
Amorphous carbon
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Summary:Temperature dependence of dc conductivity in hydrogenated amorphous carbon (a-C:H) samples, deposited in the range of −200 to −700 V self-bias voltages, was studied above room temperature from 300 K to 650 K. Because a non-Arrhenius dependence on 1/ T was found, actual activation energy E act was determined by derivation of the log σ versus T −1. This E act increased gradually with temperature by a rate depending on self bias. Strong fluctuations of E act, observed above 500 K, indicates a transition to another conduction mechanism. Below 500 K the plot of log σ versus T −1/4 could be fitted to linear functions, with an unrealistic density of states at Fermi energy, supporting, that underlying mechanism cannot be variable range hopping near E F rather it is related to conduction by hopping of carriers excited to band tails.
ISSN:0022-3093
1873-4812
DOI:10.1016/S0022-3093(98)00253-1