Density and localized states' impact on amorphous carbon electron transport mechanisms

S. Caicedo-Dávila, O. Lopez-Acevedo, J. Velasco-Medina, A. Avila

Tutkimustuotos: LehtiartikkeliArticleScientificvertaisarvioitu

1 Sitaatiot (Scopus)
185 Lataukset (Pure)

Abstrakti

This work discusses the electron transport mechanisms that we obtained as a function of the density of amorphous carbon (a-C) ultra-thin films. We calculated the density of states (total and projected), degree of electronic states' localization, and transmission function using the density functional theory and nonequilibrium Green's functions method. We generated 25 sample a-C structures using ab-initio molecular dynamics within the isothermal-isobaric ensemble. We identified three transport regimes as a function of the density, varying from semimetallic in low-density samples ( ≤2.4 g/cm3) to thermally activated in high-density ( ≥2.9 g/cm3) tetrahedral a-C. The middle-range densities (2.4 g/cm3 ≤ρ≤ 2.9 g/cm3) are characterized by resonant tunneling and hopping transport. Our findings offer a different perspective from the tight-binding model proposed by Katkov and Bhattacharyya [J. Appl. Phys. 113, 183712 (2013)], and agree with experimental observations in low-dimensional carbon systems [see S. Bhattacharyya, Appl. Phys. Lett. 91, 21 (2007)]. Identifying transport regimes is crucial to the process of understanding and applying a-C thin film in electronic devices and electrode coating in biosensors.

AlkuperäiskieliEnglanti
Artikkeli214303
Sivut1-9
JulkaisuJournal of Applied Physics
Vuosikerta120
Numero21
DOI - pysyväislinkit
TilaJulkaistu - 7 joulukuuta 2016
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

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