Two-Dimensional Palladium Diselenide with Strong In-Plane Optical Anisotropy and High Mobility Grown by Chemical Vapor Deposition
- Chinese Academy of Sciences (CAS), Beijing (China); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Ulsan National Inst. of Science and Technology (UNIST) (South Korea)
- Univ. of Tennessee, Knoxville, TN (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
- Chinese Academy of Sciences (CAS), Beijing (China)
- Ulsan National Inst. of Science and Technology (UNIST) (South Korea); Inst. for Basic Science (IBS), Ulsan (South Korea)
Two-dimensional (2D) palladium diselenide (PdSe2) has strong interlayer coupling and a puckered pentagonal structure, leading to remarkable layer-dependent electronic structures and highly anisotropic in-plane optical and electronic properties. However, the lack of high-quality, 2D PdSe2 crystals grown by bottom-up approaches limits the study of their exotic properties and practical applications. In this work, chemical vapor deposition growth of highly crystalline few-layer (≥2 layers) PdSe2 crystals on various substrates is reported. The high quality of the PdSe2 crystals is confirmed by low-frequency Raman spectroscopy, scanning transmission electron microscopy, and electrical characterization. In addition, strong in-plane optical anisotropy is demonstrated via polarized Raman spectroscopy and second-harmonic generation maps of the PdSe2 flakes. A theoretical model based on kinetic Wulff construction theory and density functional theory calculations is developed and described the observed evolution of “square=like” shaped PdSe2 crystals into rhombus due to the higher nucleation barriers for stable attachment on the (1,1) and (1,-1) edges, which results in their slower growth rates. Finally, few-layer PdSe2 field-effect transistors reveal tunable ambipolar charge carrier conduction with an electron mobility up to ≈294 cm2 V-1 s-1, which is comparable to that of exfoliated PdSe2, indicating the promise of this anisotropic 2D material for electronics.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; China Scholarship Council; Institute for Basic Science
- Grant/Contract Number:
- AC05-00OR22725; 201704910555; IBS-R019-D1
- OSTI ID:
- 1649489
- Alternate ID(s):
- OSTI ID: 1604823
- Journal Information:
- Advanced Materials, Vol. 32, Issue 19; ISSN 0935-9648
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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