Kamat Aditya, K Gurukrishna, Kumar Rishow, Mishra Abhishek, Verma Amit Kumar, Tripathi Shivam, Garg Ashish, Misra Shikhar
Department of Materials Science and Engineering, Indian Institute of Technology Kanpur Kalyanpur Kanpur India 208016
Department of Electrical Engineering, Indian Institute of Technology Kanpur Kalyanpur Kanpur India 208016.
Nanoscale Adv. 2024 Sep 3;6(22):5625-35. doi: 10.1039/d4na00682h.
The Metal to Insulator Transition (MIT) in materials, particularly vanadium dioxide (VO), has garnered significant research interest due to its potential applications in smart windows, memristors, transistors, sensors, and optical switches. The transition from an insulating, monoclinic phase to a conducting, tetragonal phase involves changes in optical and electrical properties, opening avenues in adaptive radiative coolers, optical memories, photodetectors, and optical switches. VO exhibits MIT close to 68 °C, thereby requiring tuneable transition temperatures ( ) in VO thin films for practical device applications. In this work, we explore the role of strain and defect engineering in tuning the MIT temperature in epitaxial VO thin films deposited on -cut sapphire using Pulsed Laser Deposition (PLD). The study involves tuning the metal-to-insulator transition (MIT) by varying growth parameters, mainly temperature and oxygen partial pressure. Strain engineering along the -axis helped tune the transition temperature from 65 °C to 82 °C with the out-of-plane -strain varying from -0.71% to -0.44%. Comprehensive structural and property analyses, including X-ray diffraction (XRD), Reciprocal Space Mapping (RSM), X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy, and resistivity-temperature (-) measurements, were performed to correlate structural properties with . Additionally, density functional theory (DFT) calculations were performed using Quantum Espresso within the generalized gradient approximation of the revised Perdew-Burke-Ernzerhof (PBEsol) functional to provide theoretical validity to the experimentally obtained results. Our study provides critical insights into the interplay between strain and oxygen vacancies and their effect on the physical properties of VO thin films with DFT calculations supporting the experimental findings.
材料中的金属-绝缘体转变（MIT），特别是二氧化钒（VO₂），因其在智能窗户、忆阻器、晶体管、传感器和光开关等方面的潜在应用而引起了广泛的研究兴趣。从绝缘的单斜相到导电的四方相的转变涉及光学和电学性质的变化，为自适应辐射冷却器、光学存储器、光电探测器和光开关开辟了道路。VO₂在接近68°C时表现出MIT，因此对于实际器件应用，需要在VO₂薄膜中实现可调节的转变温度（ ）。在这项工作中，我们探索了应变和缺陷工程在调节使用脉冲激光沉积（PLD）在切割蓝宝石上沉积的外延VO₂薄膜的MIT温度方面的作用。该研究涉及通过改变生长参数（主要是温度和氧分压）来调节金属-绝缘体转变（MIT）。沿轴的应变工程有助于将转变温度从65°C调节到82°C，面外应变从-0.71%变化到-0.44%。进行了包括X射线衍射（XRD）、倒易空间映射（RSM）、X射线光电子能谱（XPS）、拉曼光谱和电阻率-温度（-）测量在内的综合结构和性能分析，以将结构性能与 相关联。此外，使用量子浓缩咖啡在修订的Perdew-Burke-Ernzerhof（PBEsol）泛函的广义梯度近似内进行了密度泛函理论（DFT）计算，为实验获得的结果提供理论有效性。我们的研究通过DFT计算支持实验结果，提供了对应变和氧空位之间相互作用及其对VO₂薄膜物理性能影响的关键见解。
