Confocal Raman microscopy across the metal-insulator transition of single vanadium dioxide nanoparticles.
We present the first Raman scattering measurements on nanoparticulate vanadium dioxide (VO(2)), as well as the first observations of the temperature-induced phase transition in individual VO(2) nanoparticles (NPs). We compare the Raman response of two VO(2) NPs and a companion VO(2) film undergoing their monoclinic-tetragonal-monoclinic transformations and offer qualitative explanations for the large observed differences in hysteresis width. While bulk crystals and contiguous films contain numerous nucleation sites, individual NPs likely harbor only a few, which may make it possible to correlate detectable defects (e.g., grain boundaries and dislocations) with the "ease" of switching phases, as quantified by the width of the thermal hysteresis.
Donev
Eugenii U
EU
Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA. eugene.donev@uky.edu
Lopez
Rene
R
Feldman
Leonard C
LC
Haglund
Richard F
RF