Investigation of Copper(I) Oxide Quantum Dots by Near-Edge X-ray-Absorption Fine-Structure Spectroscopy

Authors

Ponnusamy Nachimuthu, University of Nevada, Las VegasFollow
Suntharampillai Thevuthasan, Pacific Northwest National LaboratoryFollow
Yong J. Kim, Hanbat National University, KoreaFollow
Alan S. Lea, Pacific Northwest National Laboratory
Vaithiyalingam Shutthanandan, Pacific Northwest National LaboratoryFollow
Mark H. Engelhard, Pacific Northwest National LaboratoryFollow
Donald R. Baer, Pacific Northwest National Laboratory
Scott A. Chambers, Pacific Northwest National Laboratory
David K. Shuh, Lawrence Berkeley National LaboratoryFollow
Dennis W. Lindle, University of Nevada, Las VegasFollow
Eric M. Gullikson, Lawrence Berkeley National LaboratoryFollow
Rupert C. Perera, Lawrence Berkeley National LaboratoryFollow

Document Type

Article

Publication Date

10-2003

Publication Title

Chemistry of Materials

Volume

15

Issue

20

First page number:

3939

Last page number:

3946

Abstract

Copper(I) oxide quantum dots (OQDs) were grown in various thicknesses on different SrTiO₃(001) surfaces and were investigated by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The experimental growth conditions for the OQDs were optimized to obtain Cu₂O as the major phase. The OQDs grown on clean SrTiO₃(001) surfaces at 825 K and higher with p(O₂) of 9.0 × 10^-7 Torr or greater contain mostly CuO, contrasting to OQDs grown at 800 K with p(O₂) of 7.0 × 10^-7 Torr that contain primarily Cu₂O. Furthermore, there is a strong interaction between the SrTiO₃(001) surface and the first few monolayers of the OQDs, which induces the formation of Cu(II). However, this interaction is mitigated with increasing thickness of OQDs, resulting in the exclusive formation of Cu₂O in the topmost layers. The influence of the SrTiO₃(001) substrate on the formation of OQDs can be minimized by modifying the substrate surface using chemical treatment and/or energetic Au²⁺ ion-beam irradiation. Examination of the photochemical properties of these OQDs shows that prolonged soft X-ray irradiation under vacuum reduces Cu(II), which is present as a minor impurity in the Cu(I) OQDs.

Keywords

Copper oxide; Quantum dots; Strontium compounds; X-ray Absorption Near Edge Structure

Disciplines

Analytical Chemistry | Atomic, Molecular and Optical Physics | Biological and Chemical Physics | Elementary Particles and Fields and String Theory | Physical Chemistry

Language

English

Permissions

Use Find in Your Library, contact the author, or use interlibrary loan to garner a copy of the article. Publisher copyright policy allows author to archive post-print (author’s final manuscript). When post-print is available or publisher policy changes, the article will be deposited

Repository Citation

Nachimuthu, P., Thevuthasan, S., Kim, Y. J., Lea, A. S., Shutthanandan, V., Engelhard, M. H., Baer, D. R., Chambers, S. A., Shuh, D. K., Lindle, D. W., Gullikson, E. M., Perera, R. C. (2003). Investigation of Copper(I) Oxide Quantum Dots by Near-Edge X-ray-Absorption Fine-Structure Spectroscopy. Chemistry of Materials, 15(20), 3939-3946.