Issue 13, 2024

Analytical electron microscopy analysis of insulating and metallic phases in nanostructured vanadium dioxide

Abstract

Vanadium dioxide (VO2) is a strongly correlated material that exhibits the insulator-to-metal transition (IMT) near room temperature, which makes it a promising candidate for applications in nanophotonics or optoelectronics. However, creating VO2 nanostructures with the desired functionality can be challenging due to microscopic inhomogeneities that can significantly impact the local optical and electronic properties. Thin lamellas, produced by focused ion beam milling from a homogeneous layer, provide a useful prototype for studying VO2 at the truly microscopic level using a scanning transmission electron microscope (STEM). High-resolution imaging is used to identify structural inhomogeneities while electron energy-loss spectroscopy (EELS) supported by statistical analysis helps to detect VxOy stoichiometries with a reduced oxidation number of vanadium at the areas of thickness below 70 nm. On the other hand, the thicker areas are dominated by vanadium dioxide, where the signatures of the IMT are detected in both core-loss and low-loss EELS experiments with in situ heating. The experimental results are interpreted with ab initio and semi-classical calculations. This work shows that structural inhomogeneities such as pores and cracks present no harm to the desired optical properties of VO2 samples.

Graphical abstract: Analytical electron microscopy analysis of insulating and metallic phases in nanostructured vanadium dioxide

Supplementary files

Article information

Article type
Paper
Submitted
24 Apr 2024
Accepted
02 May 2024
First published
03 May 2024
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2024,6, 3338-3346

Analytical electron microscopy analysis of insulating and metallic phases in nanostructured vanadium dioxide

J. Krpenský, M. Horák, J. Kabát, J. Planer, P. Kepič, V. Křápek and A. Konečná, Nanoscale Adv., 2024, 6, 3338 DOI: 10.1039/D4NA00338A

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