Layer-Dependent and In-Plane Anisotropic Properties of Low-Temperature Synthesized Few-Layer PdSe2 Single Crystals
- 1 April 2020
- journal article
- research article
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 14 (4), 4963-4972
- https://doi.org/10.1021/acsnano.0c01139
Abstract
Palladium diselenide (PdSe2), a peculiar noble metal dichalcogenide, has emerged as a new two-dimensional material with high predicted carrier mobility and widely tunable bandgap for device applications. The inherent in-plane anisotropy endowed by the pentagonal structure further renders PdSe2 promise for novel electronic, photonic and thermoelectric applications. However, the direct synthesis of few-layer PdSe2 is still challenging and rarely reported. Here we demonstrate that few-layer, single-crystal PdSe2 flakes can be synthesized at a relatively low growth temperature (300 °C) on sapphire substrates using low-pressure chemical vapor deposition (CVD). The well-defined rectangular domain shape and precisely determined layer number of the CVD-grown PdSe2 enable us to investigate their layer-dependent and in-plane anisotropic properties. The experimentally determined layer-dependent bandgap shrinkage combined with first-principle calculations suggest that the interlayer interaction is weaker in few-layer PdSe2 in comparison with that in bulk crystals. Field-effect transistors based on the CVD-grown PdSe2 also show performances comparable to those based on exfoliated samples. The low-temperature synthesis method reported here provides a feasible approach to fabricate high-quality few-layer PdSe2 for device applications.Keywords
Funding Information
- Ministry of Science and Technology, Taiwan (MOST-105-2119-M-002-046-MY3, MOST-107-2112-M-009-024-MY3, MOST-108-2119-M-009-011-MY3)
- Center for Emergent Functional Matter Science, National Chiao Tung University
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