Ukraine, Oles Honchar Dnipro National University.

The metal-semiconductor phase transition (MSPT) in vanadium dioxide is accompanied by an abrupt change in a number of physical parameters of this compound, in particular the resistivity. Of great interest are glass-ceramic materials, which are synthesized on the basis of vanadium dioxide and glass of the V₂O₅ - P₂O₅ system. Electronic devices based on such materials can operate at high electric currents. This allows you to create elements known as threshold switches and critical thermistors. This paper presents the results of the study of electrical conductivity and microstructure of thermosensitive glass-ceramics synthesized on the basis of fine crystalline VO₂ with crystal sizes of 5-10 μm and on the basis of nanocrystalline VO₂ (crystal size 70-100 nm). In general, microstructures are typical for such materials and contain crystals of vanadium dioxide, inclusions of vanadium phosphate glass and other components of glass ceramics. There are also pores in the microstructure of the samples. The temperature dependences of the resistivity for both types of glass-ceramics have a sharp change in the resistivity by 1.5-2 decades in the region of 70°C, which is characteristic of the MSPT in vanadium dioxide. For both types of glass-ceramics, a comparative study of the resistivity during cycling through the phase transition temperature in VO₂ was performed. Glass-ceramic samples synthesized on the basis of nanocrystalline VO₂ showed much more stable behavior. This allows creating a stable glass-ceramic material for thermistors with a critical temperature of about 70°C.

Keywords: glass-ceramics, vanadium dioxide, electrical conductivity, microstructure.

1. Bugayev A.A., Zakharchenya B.P., Chudnovskiy F.A. Fazovyy perekhod metall - poluprovodnik i yego primeneniye [Metal-semiconductor phase transition and its application]. Leningrad, Nauka, 1979, 116 p. (Rus)
2. Ren H., Li B., X. Zhou et al. Wafer-size VO2 film prepared by water-vapor oxidant. Applied Surface Science, 2020, vol. 525, p. 146642. https://doi.org/10.1016/j.apsusc.2020.146642
3. Wu C., Wang Y., Ma G. Microfabrication of VO2 thin films via a photosensitive sol-gel method. Coatings, 2021, vol. 11, iss. 10, pp. 1264. https://doi.org/10.3390/coatings11101264
4. Li G., Zhou Q., Ge L. et al. Influence of micro-structure on modulation properties in VO2 composite terahertz memory metamaterials. Optics Express, 2020, vol. 28, iss. 21, pp. 31436. https://doi.org/10.1364/OE.404082
5. Petukhova Y.V., Kudinova A.A., Bobrysheva N.P. et al. Polymer composites containing dispersed VO2 of various polymorphs: Effects of polymer matrix on functional properties. Materials Chemistry and Physics, 2019, vol. 235, pp. 121752. https://doi.org/10.1016/j.matchemphys.2019.121752
6. Ke Y., Wang S., Liu G. et al. Vanadium Dioxide: The Multistimuli Responsive Material and Its Applications. Nano-Micro Small, 2018, vol. 14, iss. 39, pp. 1802025. https://doi.org/10.1002/smll.201802025
7. Kim H.-N., Yang S. Responsive smart windows from nanoparticle - polymer composites. Advanced Functional Materials, 2019, vol. 30, iss. 2, pp. 1902597. https://doi.org/10.1002/adfm.201902597
8. John J., Gutierrez Y., Zhang Zh. Et al. Multipolar resonances with designer tunability using VO2 phase-change materials. Physical Review Applied, 2020, vol. 13, iss. 4, pp. 044053. https://doi.org/10.1103/PhysRevApplied.13.044053
9. Tonkoshkur A. S., Ivanchenko A. V. Using a layer based on materials with a metal to semiconductor phase transition for electrothermal protection of solar cells. Tekhnologiya i Konstruirovanie v Elektronnoi Apparature, 2021, no. 3-4, pp. 57-64. (Ukr) http://dx.doi.org/10.15222/TKEA2021.3-4.57
10. Ivon A.I., Kuz'menko Ye.N. [Using critical thermistors to protect the processor from overheating]. System technologies, 2007, vol. 2, no 49, pp. 25 - 32. (Rus)
11. Li D.X., Huang W.X, Song L.W., Shi Q.W. The Stability Study on Vanadium Dioxide. Advanced Materials Research, 2015, vol. 1120-1121, pp.158-167. https://doi.org/10.4028/www.scientific.net/AMR.1120-1121.158
12. Ivon A.I., Kolbunov V.R., Chernenko I.M. Conductivity stabilization by metal and oxide additives in ceramics on the basis of VO2 and glass V2O5-P2O5. Journal of Non-Crystalline Solids. 2005, vol. 351, iss. 46-48, pp. 3649-3654. https://doi.org/10.1016/j.jnoncrysol.2005.08.035
13. Chernenko I.M., Ivon O.I., Kolbunov V.R., Oliynyk O.Yu. [Method of producing nanodispersed vanadium dioxide]. Pat. UA no. 100940, 2013, bull. 3. (Ukr)
14. Vasylenko V.Ya., Yvon A.Y., Chernenko Y.M. [Electrosynthesis of single crystals of VO2 in oxide vanadium-phosphate melts]. Crystallografija, 1983, vol. 28, no 4, 830 p. (Rus)
15. Kolbunov V.R., Ivon A.I., Kunitskiy Y.A., Chernenko I.M. The influence of microstructure and phase composition of glass-ceramics in the VO2 - V2O5 - P2O5 - Cu2O - SnO2 system on the electrical properties related to the metal-semiconductor phase transition. Ceramics International, 2013, vol. 39, iss. 4, pp. 3613-3620. https://doi.org/10.1016/j.ceramint.2012.10.189