Thermochromic VO2 thin film from electron beam evaporated V2O5/Ni/V2O5 and V2O5/Co/V2O5 multilayer stack system

被引：3

作者：

Numan, N. ^{[1
,2
]}

Simo, A. ^{[1
,2
]}

Mabakachaba, B. ^{[1
,2
]}

Madiba, I. G. ^{[1
,2
]}

Mtshali, C. B. ^{[2
]}

Khumalo, Z. M. ^{[2
]}

Mongwaketsi, N. ^{[2
]}

Mlungisi, N. ^{[2
]}

Maaza, M. ^{[1
,2
]}

机构：

[1] Univ South Africa, Coll Grad Studies, UNESCO UNISA Africa Chair Nanosci Nanotechnol, POB 392, Pretoria, South Africa

[2] Natl Res Fdn, iThemba LABS, Nanosci African Network NANOAFNET, 1 Old Faure Rd,Somerset West 7129,POB 722, Somerset West, Western Cape Pr, South Africa

来源：

THIN SOLID FILMS | 2023年 / 782卷

关键词：

Vanadium dioxide; Thin films; Multilayers; Phase transition; Electron beam deposition; Nickel doping; Cobalt doping; VANADIUM-DIOXIDE; INSULATOR-TRANSITION; OPTICAL-PROPERTIES; PHASE-TRANSITION; NANOSTRUCTURES; TEMPERATURE; PERFORMANCE; DEPOSITION; COATINGS; GROWTH;

D O I：

10.1016/j.tsf.2023.140033

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The oxygen-vanadium system presents different equilibrium phases amongst which monoclinic and tetragonal forms of VO2 exist below and above the phase transition temperature of 68 degrees C. The structure can be explained by pure Mott phase transition with Peierls electron-lattice distortion giving ultrafast transformation of the semiconducting monoclinic VO2 to metallic rutile structure. Hence, practical applications in technology can be explored such as; switching devices, thermal relays and energy management, sensors and actuators, electrochromic and photochromic memories. In this study, VO2 thermochromic thin films were deposited on a quartz glass substrate by electron beam evaporation technique in ultrahigh vacuum at room temperature using sandwich structured V2O5/metal (Ni, Co)/V2O5 multilayer target followed by post-annealing at 500 degrees C under vacuum. The morphology and crystal structure were investigated by X-ray diffraction, Ultraviolet/Visible/Near Infrared spectrophotometry, and scanning electron microscopy analyses. The sandwich structure effectively regulates the stoichiometry and polymorphs of the material. It was observed that the polymorph of the films switch from VO2 (B) to VO2 (M) when the Ni and Co middle layer reached 7 nm and 10 nm respectively. For the aforementioned thicknesses of the Ni and Co layers, the V2O5/Ni/V2O5 and V2O5/Co/V2O5 multilayers showed thermochromic properties. For V2O5/Ni (7 nm)/V2O5 and V2O5/Co (10 nm)/V2O5 multilayer films, the temperature-dependent spectral transmission measurements show the change in optical range of & SIM; 65% and & SIM; 43% respectively after the phase transition at wavelength 2500 nm. Transmission measurements of VO2 thin films, were determined at temperatures below and above the phase transition temperature in both the visible and the near-infrared ranges of the electromagnetic spectrum. The temperature-dependent optical transmittance measurement for V2O5/Co (10 nm)/V2O5 multilayer films shows that the multilayer exhibits thermochromic properties and has higher phase transition temperature.

引用

页数：8

共 61 条

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