Surface control of CdSe nanocrystals by UV-exposure in air and successive thermal treatment under ultra high vacuum

Hyun Ju Choi, Seok Joo Wang, Hyuncheol Kim, Hyung-Ho Park, Ho Jung Chang, Hyeongtag Jeon

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Colloidal CdSe nanocrystals were synthesized through a solution process. The CdSe nanocrystals coated on Si(1 0 0) wafers were UV-exposed in either an air or argon atmosphere to distinguish the effect of generated ozone from UV-radiation at 365 nm on the removal of surface capping pyridine molecules. The pyridine on the CdSe nanocrystal's surface could be effectively removed by the ozone generated during UV-exposure with an accompanying highly oxidized surface state of the CdSe nanocrystals. For the removal of surface oxides of CdSe nanocrystals, a successive thermal treatment under ultra high vacuum (UHV) was adopted. The optical energy bandgap measured by using UV-vis absorption spectroscopy showed a red shift with treatment with an increase of annealing temperature. The electronic energy structure of UHV-annealed CdSe nanocrystals film was analyzed in situ using X-ray absorption and photoelectron spectroscopy. A great resemblance was found between the values of the optical and electron energy bandgaps of effectively surface-treated CdSe nanocrystals film after UHV-annealing at 400 °C.

Original languageEnglish
Pages (from-to)6886-6889
Number of pages4
JournalApplied Surface Science
Volume254
Issue number21
DOIs
Publication statusPublished - 2008 Aug 30

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Control surfaces
Ultrahigh vacuum
Nanocrystals
Heat treatment
Air
Ozone
Pyridine
Energy gap
Annealing
X ray absorption spectroscopy
Argon
Surface states
Ultraviolet spectroscopy
Absorption spectroscopy
Ultraviolet radiation
Oxides
X ray photoelectron spectroscopy
Molecules
Electrons

All Science Journal Classification (ASJC) codes

  • Surfaces, Coatings and Films

Cite this

Choi, Hyun Ju ; Wang, Seok Joo ; Kim, Hyuncheol ; Park, Hyung-Ho ; Chang, Ho Jung ; Jeon, Hyeongtag. / Surface control of CdSe nanocrystals by UV-exposure in air and successive thermal treatment under ultra high vacuum. In: Applied Surface Science. 2008 ; Vol. 254, No. 21. pp. 6886-6889.
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Surface control of CdSe nanocrystals by UV-exposure in air and successive thermal treatment under ultra high vacuum. / Choi, Hyun Ju; Wang, Seok Joo; Kim, Hyuncheol; Park, Hyung-Ho; Chang, Ho Jung; Jeon, Hyeongtag.

In: Applied Surface Science, Vol. 254, No. 21, 30.08.2008, p. 6886-6889.

Research output: Contribution to journalArticle

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