Next Article in Journal
Fabrication of CH3NH3PbI3/PVP Composite Fibers via Electrospinning and Deposition
Next Article in Special Issue
Structure, Morphology and Reducibility of Epitaxial Cerium Oxide Ultrathin Films and Nanostructures
Previous Article in Journal
Effects of Fiber Reinforcement on Clay Aerogel Composites
Previous Article in Special Issue
Growth of Ceria Nano-Islands on a Stepped Au(788) Surface
Article Menu

Export Article

Open AccessArticle
Materials 2015, 8(8), 5452-5466; doi:10.3390/ma8085255

X-Ray Spectroscopy of Ultra-Thin Oxide/Oxide Heteroepitaxial Films: A Case Study of Single-Nanometer VO2/TiO2

1
Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA
2
Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA
3
Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
4
National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, NY 11973, USA
5
Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA
*
Author to whom correspondence should be addressed.
Academic Editor: Jan Ingo Flege
Received: 30 July 2015 / Revised: 12 August 2015 / Accepted: 14 August 2015 / Published: 21 August 2015
(This article belongs to the Special Issue Epitaxial Materials 2015)
View Full-Text   |   Download PDF [387 KB, uploaded 21 August 2015]   |  

Abstract

Epitaxial ultra-thin oxide films can support large percent level strains well beyond their bulk counterparts, thereby enabling strain-engineering in oxides that can tailor various phenomena. At these reduced dimensions (typically < 10 nm), contributions from the substrate can dwarf the signal from the epilayer, making it difficult to distinguish the properties of the epilayer from the bulk. This is especially true for oxide on oxide systems. Here, we have employed a combination of hard X-ray photoelectron spectroscopy (HAXPES) and angular soft X-ray absorption spectroscopy (XAS) to study epitaxial VO2/TiO2 (100) films ranging from 7.5 to 1 nm. We observe a low-temperature (300 K) insulating phase with evidence of vanadium-vanadium (V-V) dimers and a high-temperature (400 K) metallic phase absent of V-V dimers irrespective of film thickness. Our results confirm that the metal insulator transition can exist at atomic dimensions and that biaxial strain can still be used to control the temperature of its transition when the interfaces are atomically sharp. More generally, our case study highlights the benefits of using non-destructive XAS and HAXPES to extract out information regarding the interfacial quality of the epilayers and spectroscopic signatures associated with exotic phenomena at these dimensions. View Full-Text
Keywords: heteroepitaxial systems and interfaces; rational design of nanoscale materials; structure-function relationship heteroepitaxial systems and interfaces; rational design of nanoscale materials; structure-function relationship
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Quackenbush, N.F.; Paik, H.; Woicik, J.C.; Arena, D.A.; Schlom, D.G.; Piper, L.F.J. X-Ray Spectroscopy of Ultra-Thin Oxide/Oxide Heteroepitaxial Films: A Case Study of Single-Nanometer VO2/TiO2. Materials 2015, 8, 5452-5466.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top