Stabilization of the VO2(M2) Phase and Change in Lattice Parameters at the Phase Transition Temperature of WXV1- XO2 Thin Films

Artitsupa Boontan; Eric Kumi Barimah; Paul Steenson; Gin Jose

doi:10.1021/acsami.3c11484

Stabilization of the VO₂(M2) Phase and Change in Lattice Parameters at the Phase Transition Temperature of W_XV_{1- X}O₂ Thin Films

ACS Appl Mater Interfaces. 2023 Nov 8;15(44):51606-51616. doi: 10.1021/acsami.3c11484. Epub 2023 Oct 24.

Authors

Artitsupa Boontan¹, Eric Kumi Barimah¹, Paul Steenson², Gin Jose¹

Affiliations

¹ School of Chemical and Process Engineering, University of Leeds, Clarendon Road, Leeds LS2 9JT, U.K.
² School of Electronic and Electrical Engineering, University of Leeds, Clarendon Road, Leeds LS2 9JT, U.K.

Abstract

Various methods have been used to fabricate vanadium dioxide (VO₂) thin films exhibiting polymorph phases and an identical chemical formula suited to different applications. Most fabrication techniques require post-annealing to convert the amorphous VO₂ thin film into the VO₂ (M1) phase. In this study, we provide a temperature-dependent XRD analysis that confirms the change in lattice parameters responsible for the metal-to-insulator transition as the structure undergoes a monoclinic to the tetragonal phase transition. In our study, we deposited VO₂ and W-doped VO₂ thin films onto silica substrates using a high repetition rate (10 kHz) fs-PLD deposition without post-annealing. The XRD patterns measured at room temperature revealed stabilization of the monoclinic M2 phase by W⁶⁺ doping VO₂. We developed an alternative approach to determine the phase transition temperatures using temperature-dependent X-ray diffraction measurements to evaluate the a and b lattice parameters for the monoclinic and rutile phases. The a and b lattice parameters versus temperature revealed phase transition temperature reduction from ∼66 to 38 °C when the W⁶⁺ concentration increases. This study provides a novel unorthodox technique to characterize and evaluate the structural phase transitions seen on VO₂ thin films.

Keywords: M1 and M2 phases; W; doping; fs-PLD; phase transition; vanadium dioxide.