Stress-induced in situ modification of transition temperature in vo2 films capped by chalcogenide

Joe Sakai, Masashi Kuwahara, Kunio Okimura, Yoichi Uehara

研究成果: Article査読


We attempted to modify the monoclinic–rutile structural phase transition temperature (Ttr) of a VO2 thin film in situ through stress caused by amorphous–crystalline phase change of a chalcogenide layer on it. VO2 films on C-or R-plane Al2 O3 substrates were capped by Ge2 Sb2 Te5 (GST) films by means of rf magnetron sputtering. Ttr of the VO2 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 Ttr of the VO2 layer underneath, either with or without a SiNx diffusion barrier layer between the two. The shift of Ttr was by ~30 C for a GST/VO2 bilayered sample with thicknesses of 200/30 nm, and was by ~6 C for a GST/SiNx /VO2 trilayered sample of 200/10/6 nm. The lowering of Ttr was most probably caused by the volume reduction in GST during the amorphous–crystalline phase change. The stress-induced in in situ modification of Ttr in VO2 films could pave the way for the application of nonvolatile changes of optical properties in optoelectronic devices.

出版ステータスPublished - 2020 12

ASJC Scopus subject areas

  • Materials Science(all)

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