Tetrahedral amorphous carbon-silicon heterojunction band energy offsets

N. L. Rupesinghe, R. J. Cole, Manish Chhowalla, G. A J Amaratunga, P. Weightman

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Non-hydrogenated tetrahedral amorphous carbon (ta-C) has shown superior field emission characteristics. The understanding of the emission mechanism has been hindered by the lack of any directly measured data on the band offsets between ta-C and Si. In this paper results from direct in situ X-ray photoemission spectroscopy (XPS) measurements of the band-offset between ta-C and Si are reported. The measurements were carried out using a filtered cathodic vacuum arc (FCVA) deposition system attached directly to an ultra-high vacuum (UHV) XPS chamber via a load lock chamber. Repeated XPS measurements were carried out after monolayer depositions on in situ cleaned Si substrates. The total film thickness for each set of measurements was approximately 5 nm. Analysis of the data from undoped ta-C on n and p Si show the unexpected result that the conduction band barrier between Si and ta-C remains around 1.0 eV, but that the valence band barrier changes from 0.7 to 0.0 eV. The band line up derived from these barriers suggests that the Fermi level in the ta-C lies 0.3 eV above the valence band on both p and n+Si. The heterojunction barriers when ta-C is doped with nitrogen are also presented. The implications of the heterojunction energy barrier heights for field emission from ta-C are discussed.

Original languageEnglish
Pages (from-to)1148-1153
Number of pages6
JournalDiamond and Related Materials
Volume9
Issue number3
DOIs
Publication statusPublished - Apr 2000

Fingerprint

Amorphous carbon
Silicon
Band structure
energy bands
Heterojunctions
heterojunctions
carbon
silicon
Photoelectron spectroscopy
X ray spectroscopy
photoelectric emission
Valence bands
Field emission
field emission
chambers
spectroscopy
valence
x rays
Energy barriers
Ultrahigh vacuum

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this

Tetrahedral amorphous carbon-silicon heterojunction band energy offsets. / Rupesinghe, N. L.; Cole, R. J.; Chhowalla, Manish; Amaratunga, G. A J; Weightman, P.

In: Diamond and Related Materials, Vol. 9, No. 3, 04.2000, p. 1148-1153.

Research output: Contribution to journalArticle

Rupesinghe, N. L. ; Cole, R. J. ; Chhowalla, Manish ; Amaratunga, G. A J ; Weightman, P. / Tetrahedral amorphous carbon-silicon heterojunction band energy offsets. In: Diamond and Related Materials. 2000 ; Vol. 9, No. 3. pp. 1148-1153.
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