Fig. 7: Temperature-dependent X-ray diffractograms of VO₂ thin films and heterostructures.

X-ray diffractograms of a 9.5VO₂, b 9.5VO₂-het, and c 4.5VO₂-het measured in the insulating phase (at 200 K) and the metallic phase (at 320 K) of VO₂. VO₂ (\(\bar{4}02\))_M and (002)_R reflections can be clearly distinguished for all the heterostructures studied in this work. The \((\bar{4}02)\)_M peak is the out-of-plane (of the substrate) Bragg reflection in the monoclinic phase of VO₂ while (002)_R is the out-of-plane reflection in the rutile phase. d A comparison of temperature-dependent XRD spectra of the 4.5VO₂-het film measured at 200 K, 280 K, and 320 K. The XRD spectrum measured at 280 K shows rutile phase characteristics like the one measured at 320 K suggesting that VO₂ remains in the rutile phase at 280 K in the 4.5 nm VO₂ heterostructure.