{"title":"射频溅射VO2薄膜中金属-绝缘体跃迁和低温电荷输运的衬底诱导调制","authors":"Akash Kumar Singh , Suman Kumari , H.K. Singh , P.K. Siwach","doi":"10.1016/j.tsf.2025.140773","DOIUrl":null,"url":null,"abstract":"<div><div>In this study, we investigate the influence of substrate type on the phase transition behavior and charge transport characteristics of polycrystalline VO<sub>2</sub> films grown by Radio Frequency (RF) magnetron sputtering of a V<sub>2</sub>O<sub>5</sub> target in pure argon ambient at ∼700 °C. The films were deposited on five single-crystal substrates namely, Yttria Stabilized Zirconia [YSZ (001)], Lanthanum Aluminate [LAO (100)], Magnesium Oxide [MgO (100)], c-plane Sapphire [ALO (0001)], and Zinc Oxide [ZnO (0001)]. Structural and Raman analysis confirmed the dominance of the VO<sub>2</sub> phase with minor secondary V-O phases. Surface morphology revealed substrate-dependent uniformity and grain structure. Films on YSZ (001), LAO (100), and MgO (100) exhibited a sharp and reversible Insulator-Metal/Metal-Insulator transition (IMT/MIT) around ∼(339–341 K/66–68 °C), with narrow Thermal hysteresis (T<sub>H</sub>) varies from ∼(4–8 K) and a two-order resistivity change. In contrast, films on ALO (0001) and ZnO (0001) showed broader transitions, lower transition temperatures (T<sub>IM</sub>/T<sub>MI</sub> ∼331–337 K/58–64 °C), and reduced resistivity change, particularly on ZnO (0001), which displayed a single-order transition with a larger hysteresis (∼10 K). The Temperature Coefficient of Resistance/Resistivity (TCR) showed trends consistent with resistivity behavior, reaching values as high as −98 % K<sup>-1</sup> near the IMT/MIT. Activation energy (E<sub>A</sub>) in the insulating phase varied significantly with substrate, from ∼0.221 eV (MgO) to ∼0.395 eV (ZnO), and low-temperature conduction (300 K ≤ <em>T</em> ≤ 4.2 K) revealed a crossover from Efros–Shklovskii Variable Range Hopping (ES-VRH) on symmetric substrates [YSZ (001), LAO (100), MgO (100)] to Nearest-Neighbor Hopping (NN<img>H) on ALO (0001) and ZnO (0001). These results underline the critical role of substrate symmetry and orientation in tailoring the phase transition dynamics and transport mechanisms in VO<sub>2</sub> films, providing useful guidelines for substrate-engineered VO<sub>2</sub>-based device applications.</div></div>","PeriodicalId":23182,"journal":{"name":"Thin Solid Films","volume":"826 ","pages":"Article 140773"},"PeriodicalIF":2.0000,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Substrate-induced modulation of metal-insulator transition and low-temperature charge transport in radio frequency sputtered VO2 films\",\"authors\":\"Akash Kumar Singh , Suman Kumari , H.K. Singh , P.K. Siwach\",\"doi\":\"10.1016/j.tsf.2025.140773\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>In this study, we investigate the influence of substrate type on the phase transition behavior and charge transport characteristics of polycrystalline VO<sub>2</sub> films grown by Radio Frequency (RF) magnetron sputtering of a V<sub>2</sub>O<sub>5</sub> target in pure argon ambient at ∼700 °C. The films were deposited on five single-crystal substrates namely, Yttria Stabilized Zirconia [YSZ (001)], Lanthanum Aluminate [LAO (100)], Magnesium Oxide [MgO (100)], c-plane Sapphire [ALO (0001)], and Zinc Oxide [ZnO (0001)]. Structural and Raman analysis confirmed the dominance of the VO<sub>2</sub> phase with minor secondary V-O phases. Surface morphology revealed substrate-dependent uniformity and grain structure. Films on YSZ (001), LAO (100), and MgO (100) exhibited a sharp and reversible Insulator-Metal/Metal-Insulator transition (IMT/MIT) around ∼(339–341 K/66–68 °C), with narrow Thermal hysteresis (T<sub>H</sub>) varies from ∼(4–8 K) and a two-order resistivity change. In contrast, films on ALO (0001) and ZnO (0001) showed broader transitions, lower transition temperatures (T<sub>IM</sub>/T<sub>MI</sub> ∼331–337 K/58–64 °C), and reduced resistivity change, particularly on ZnO (0001), which displayed a single-order transition with a larger hysteresis (∼10 K). The Temperature Coefficient of Resistance/Resistivity (TCR) showed trends consistent with resistivity behavior, reaching values as high as −98 % K<sup>-1</sup> near the IMT/MIT. Activation energy (E<sub>A</sub>) in the insulating phase varied significantly with substrate, from ∼0.221 eV (MgO) to ∼0.395 eV (ZnO), and low-temperature conduction (300 K ≤ <em>T</em> ≤ 4.2 K) revealed a crossover from Efros–Shklovskii Variable Range Hopping (ES-VRH) on symmetric substrates [YSZ (001), LAO (100), MgO (100)] to Nearest-Neighbor Hopping (NN<img>H) on ALO (0001) and ZnO (0001). These results underline the critical role of substrate symmetry and orientation in tailoring the phase transition dynamics and transport mechanisms in VO<sub>2</sub> films, providing useful guidelines for substrate-engineered VO<sub>2</sub>-based device applications.</div></div>\",\"PeriodicalId\":23182,\"journal\":{\"name\":\"Thin Solid Films\",\"volume\":\"826 \",\"pages\":\"Article 140773\"},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2025-08-16\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Thin Solid Films\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0040609025001725\",\"RegionNum\":4,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATERIALS SCIENCE, COATINGS & FILMS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Thin Solid Films","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0040609025001725","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, COATINGS & FILMS","Score":null,"Total":0}
Substrate-induced modulation of metal-insulator transition and low-temperature charge transport in radio frequency sputtered VO2 films
In this study, we investigate the influence of substrate type on the phase transition behavior and charge transport characteristics of polycrystalline VO2 films grown by Radio Frequency (RF) magnetron sputtering of a V2O5 target in pure argon ambient at ∼700 °C. The films were deposited on five single-crystal substrates namely, Yttria Stabilized Zirconia [YSZ (001)], Lanthanum Aluminate [LAO (100)], Magnesium Oxide [MgO (100)], c-plane Sapphire [ALO (0001)], and Zinc Oxide [ZnO (0001)]. Structural and Raman analysis confirmed the dominance of the VO2 phase with minor secondary V-O phases. Surface morphology revealed substrate-dependent uniformity and grain structure. Films on YSZ (001), LAO (100), and MgO (100) exhibited a sharp and reversible Insulator-Metal/Metal-Insulator transition (IMT/MIT) around ∼(339–341 K/66–68 °C), with narrow Thermal hysteresis (TH) varies from ∼(4–8 K) and a two-order resistivity change. In contrast, films on ALO (0001) and ZnO (0001) showed broader transitions, lower transition temperatures (TIM/TMI ∼331–337 K/58–64 °C), and reduced resistivity change, particularly on ZnO (0001), which displayed a single-order transition with a larger hysteresis (∼10 K). The Temperature Coefficient of Resistance/Resistivity (TCR) showed trends consistent with resistivity behavior, reaching values as high as −98 % K-1 near the IMT/MIT. Activation energy (EA) in the insulating phase varied significantly with substrate, from ∼0.221 eV (MgO) to ∼0.395 eV (ZnO), and low-temperature conduction (300 K ≤ T ≤ 4.2 K) revealed a crossover from Efros–Shklovskii Variable Range Hopping (ES-VRH) on symmetric substrates [YSZ (001), LAO (100), MgO (100)] to Nearest-Neighbor Hopping (NNH) on ALO (0001) and ZnO (0001). These results underline the critical role of substrate symmetry and orientation in tailoring the phase transition dynamics and transport mechanisms in VO2 films, providing useful guidelines for substrate-engineered VO2-based device applications.
期刊介绍:
Thin Solid Films is an international journal which serves scientists and engineers working in the fields of thin-film synthesis, characterization, and applications. The field of thin films, which can be defined as the confluence of materials science, surface science, and applied physics, has become an identifiable unified discipline of scientific endeavor.