Band-gap measurements of bulk and nanoscale hematite by soft x-ray spectroscopy

Research output: Contribution to journalJournal article – Annual report year: 2009Researchpeer-review

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Band-gap measurements of bulk and nanoscale hematite by soft x-ray spectroscopy. / Gilbert, B.; Frandsen, Cathrine; Maxey, E.R.; Sherman, D.M.

In: Physical Review B Condensed Matter, Vol. 79, No. 3, 2009, p. 035108.

Research output: Contribution to journalJournal article – Annual report year: 2009Researchpeer-review

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@article{f54d50630b674c6da0933e2a7adf1a89,
title = "Band-gap measurements of bulk and nanoscale hematite by soft x-ray spectroscopy",
abstract = "Chemical and photochemical processes at semiconductor surfaces are highly influenced by the size of the band gap, and ability to control the band gap by particle size in nanomaterials is part of their promise. The combination of soft x-ray absorption and emission spectroscopies provides band-gap determination in bulk and nanoscale itinerant electron semiconductors such as CdS and ZnO, but this approach has not been established for materials such as iron oxides that possess band-edge electronic structure dominated by electron correlations. We performed soft x-ray spectroscopy at the oxygen K-edge to reveal band-edge electronic structure of bulk and nanoscale hematite. Good agreement is found between the hematite band gap derived from optical spectroscopy and the energy separation of the first inflection points in the x-ray absorption and emission onset regions. By applying this method to two sizes of phase-pure hematite nanoparticles, we find that there is no evidence for size-driven change in the band gap of hematite nanoparticles down to around 8 nm.",
keywords = "energy gap, X-ray absorption spectra, X-ray emission spectra, nanostructured materials, iron compounds",
author = "B. Gilbert and Cathrine Frandsen and E.R. Maxey and D.M. Sherman",
note = "Copyright 2009 American Physical Society",
year = "2009",
doi = "10.1103/PhysRevB.79.035108",
language = "English",
volume = "79",
pages = "035108",
journal = "Physical Review B (Condensed Matter and Materials Physics)",
issn = "1098-0121",
publisher = "American Physical Society",
number = "3",

}

RIS

TY - JOUR

T1 - Band-gap measurements of bulk and nanoscale hematite by soft x-ray spectroscopy

AU - Gilbert, B.

AU - Frandsen, Cathrine

AU - Maxey, E.R.

AU - Sherman, D.M.

N1 - Copyright 2009 American Physical Society

PY - 2009

Y1 - 2009

N2 - Chemical and photochemical processes at semiconductor surfaces are highly influenced by the size of the band gap, and ability to control the band gap by particle size in nanomaterials is part of their promise. The combination of soft x-ray absorption and emission spectroscopies provides band-gap determination in bulk and nanoscale itinerant electron semiconductors such as CdS and ZnO, but this approach has not been established for materials such as iron oxides that possess band-edge electronic structure dominated by electron correlations. We performed soft x-ray spectroscopy at the oxygen K-edge to reveal band-edge electronic structure of bulk and nanoscale hematite. Good agreement is found between the hematite band gap derived from optical spectroscopy and the energy separation of the first inflection points in the x-ray absorption and emission onset regions. By applying this method to two sizes of phase-pure hematite nanoparticles, we find that there is no evidence for size-driven change in the band gap of hematite nanoparticles down to around 8 nm.

AB - Chemical and photochemical processes at semiconductor surfaces are highly influenced by the size of the band gap, and ability to control the band gap by particle size in nanomaterials is part of their promise. The combination of soft x-ray absorption and emission spectroscopies provides band-gap determination in bulk and nanoscale itinerant electron semiconductors such as CdS and ZnO, but this approach has not been established for materials such as iron oxides that possess band-edge electronic structure dominated by electron correlations. We performed soft x-ray spectroscopy at the oxygen K-edge to reveal band-edge electronic structure of bulk and nanoscale hematite. Good agreement is found between the hematite band gap derived from optical spectroscopy and the energy separation of the first inflection points in the x-ray absorption and emission onset regions. By applying this method to two sizes of phase-pure hematite nanoparticles, we find that there is no evidence for size-driven change in the band gap of hematite nanoparticles down to around 8 nm.

KW - energy gap

KW - X-ray absorption spectra

KW - X-ray emission spectra

KW - nanostructured materials

KW - iron compounds

U2 - 10.1103/PhysRevB.79.035108

DO - 10.1103/PhysRevB.79.035108

M3 - Journal article

VL - 79

SP - 035108

JO - Physical Review B (Condensed Matter and Materials Physics)

JF - Physical Review B (Condensed Matter and Materials Physics)

SN - 1098-0121

IS - 3

ER -