Abstract
Most studied two-dimensional (2D) materials exhibit isotropic behavior due to high lattice symmetry; however, lower-symmetry 2D materials such as phosphorene and other elemental 2D materials exhibit very interesting anisotropic properties. In this work, we report the atomic structure, electronic properties, and vibrational modes of few-layered PdSe2 exfoliated from bulk crystals, a pentagonal 2D layered noble transition metal dichalcogenide with a puckered morphology that is air-stable. Micro-absorption optical spectroscopy and first-principles calculations reveal a wide band gap variation in this material from 0 (bulk) to 1.3 eV (monolayer). The Raman-active vibrational modes of PdSe2 were identified using polarized Raman spectroscopy, and a strong interlayer interaction was revealed from large, thickness-dependent Raman peak shifts, agreeing with first-principles Raman simulations. Field-effect transistors made from the few-layer PdSe2 display tunable ambipolar charge carrier conduction with a high electron field-effect mobility of ∼158 cm2 V-1 s-1, indicating the promise of this anisotropic, air-stable, pentagonal 2D material for 2D electronics.
| Original language | English |
|---|---|
| Pages (from-to) | 14090-14097 |
| Number of pages | 8 |
| Journal | Journal of the American Chemical Society |
| Volume | 139 |
| Issue number | 40 |
| DOIs | |
| State | Published - Oct 11 2017 |
Funding
This research was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. A.D.O. acknowledges fellowship support from the UT/ORNL Bredesen Center for Interdisciplinary Research and Graduate Education. The single-crystal growth was supported by Singapore National Research Foundation under NRF RF Award No. NRF-RF2013-08. The electron microscopy was supported by the Materials Science and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy and through a user project at ORNL’s Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility. L.L. was supported by Eugene P. Wigner Fellowship at the Oak Ridge National Laboratory (ORNL). J.Z. was supported by Graduate Opportunities “GO!” program at ORNL. Part of the computations were performed using the resources of the Center for Computational Innovation at Rensselaer Polytechnic Institute. P.R.P. and P.D.R. acknowledge support by the U.S. Department of Energy (DOE) under Grant No. DOE DE-SC0002136.