Calcium fluoride is a dielectric material with a wide bandgap (∼12.1 eV) and a relatively high dielectric constant (∼6.8) that forms a van der Waals interface with two-dimensional (2D) materials, meaning that it contains a very low amount of defects. Thin calcium fluoride films can be synthesized using multiple techniques that are scalable to the wafer level, including molecular beam epitaxy, atomic layer deposition, and chemical vapor deposition. However, the consolidation of calcium fluoride as dielectric for 2D electronics requires overcoming some fundamental challenges related to material quality and integration, as well as carrying out advanced characterization and computational studies to evaluate its real potential. Here, we review the status of calcium fluoride dielectric films in terms of material synthesis, fundamental electrical properties, and future applications; we also discuss the most important challenges of calcium fluoride integration in 2D materials-based, solid-state nano/micro-electronic devices, and propose several potential routes to overcome them. Our manuscript may serve as a useful guide for other scientists working on 2D electronics in general, and provides a clear pathway for calcium fluoride research in the future.
Bibliographical noteKAUST Repository Item: Exported on 2021-04-19
Acknowledgements: M.L. acknowledges generous start-up support from the Baseline funding scheme of the King Abdullah University of Science and Technology. This work has also been partially supported by the Ministry of Science and Technology of China (Grants Nos. 2018YFE0100800 and 2019YFE0124200), the National Natural Science Foundation of China (Grant No. 61874075), the Collaborative Innovation Centre of Suzhou Nano Science & Technology, the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the 111 Project from the State Administration of Foreign Experts Affairs of China. The authors thank Dr. Fernan Saiz-Poyatos for his help on the design of
Fig. 1(a), Professor Nikolai S. Sokolov and Dr. Yury Yu. Illarionov for providing the AFM topography maps in Fig. 3(a), as well as Dr.
Xu Jing for his help in redrawing Fig. 4(a) and Fig. 5(d).
ASJC Scopus subject areas
- Physics and Astronomy(all)