Negative thermal expansion ZrW 2O 8 thin films prepared by pulsed laser deposition

Abstract

Negative thermal expansion ZrW 2O 8 thin films has been grown on quartz substrates by pulsed laser deposition (PLD) method followed by annealing at various temperatures. The influences of annealing temperature on the morphology and phase composition of the ZrW 2O 8 thin films were investigated. The X-ray diffraction (XRD) and X-ray photoelectron spectroscope (XPS) analyses revealed that the as-deposited ZrW 2O 8 thin film showed an amorphous phase, the stoichiometry of the as-deposited thin film was close to that of the ZrW 2O 8 ceramic target, the crystallized cubic ZrW 2O 8 thin films were prepared after annealing at 1200 °C. The scanning electron microscope (SEM) confirmed that the ZrW 2O 8 thin film deposited on the substrate heated at 650 °C was smooth and compact, the crystallized cubic ZrW 2O 8 thin film was a polycrystalline film and its grain size grew to be larger. The high temperature X-ray diffraction analyses showed that all the peaks ascribe to the ZrW 2O 8 thin film shifted to higher angle with the increasing temperatures, which demonstrated that the cubic ZrW 2O 8 thin film exhibited negative thermal expansion and its thermal expansion coefficient was calculated to be − 11.378 × 10 −6 K −1 from 20 °C to 600 °C.