| Summary: | We attempted to modify the monoclinic–rutile structural phase transition temperature (<i>T</i><sub>tr</sub>) of a VO<sub>2</sub> thin film in situ through stress caused by amorphous–crystalline phase change of a chalcogenide layer on it. VO<sub>2</sub> films on C- or R-plane Al<sub>2</sub>O<sub>3</sub> substrates were capped by Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> (GST) films by means of rf magnetron sputtering. <i>T</i><sub>tr</sub> of the VO<sub>2</sub> layer was evaluated through temperature-controlled measurements of optical reflection intensity and electrical resistance. Crystallization of the GST capping layer was accompanied by a significant drop in <i>T</i><sub>tr</sub> of the VO<sub>2</sub> layer underneath, either with or without a SiN<i><sub>x</sub></i> diffusion barrier layer between the two. The shift of <i>T</i><sub>tr</sub> was by ~30 °C for a GST/VO<sub>2</sub> bilayered sample with thicknesses of 200/30 nm, and was by ~6°C for a GST/SiN<i><sub>x</sub></i>/VO<sub>2</sub> trilayered sample of 200/10/6 nm. The lowering of <i>T</i><sub>tr</sub> was most probably caused by the volume reduction in GST during the amorphous–crystalline phase change. The stress-induced in in situ modification of <i>T</i><sub>tr</sub> in VO<sub>2</sub> films could pave the way for the application of nonvolatile changes of optical properties in optoelectronic devices.
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