PdSe2: Pentagonal Two-Dimensional Layers with High Air Stability for Electronics
journal contributionposted on 05.09.2017, 00:00 by Akinola D. Oyedele, Shize Yang, Liangbo Liang, Alexander A. Puretzky, Kai Wang, Jingjie Zhang, Peng Yu, Pushpa R. Pudasaini, Avik W. Ghosh, Zheng Liu, Christopher M. Rouleau, Bobby G. Sumpter, Matthew F. Chisholm, Wu Zhou, Philip D. Rack, David B. Geohegan, Kai Xiao
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.
Read the peer-reviewed publication
2 D materials exhibittransition metal dichalcogenidethickness-dependent Raman peak shiftslower-symmetry 2 D materialsband gap variationfew-layer PdSe 2 display tunable ambipolar charge carrier conduction2 D electronicsfew-layered PdSe 2 exfoliatedfirst-principles Raman simulationsanisotropicHigh Air Stabilityair-stablebulkelectron field-effect mobilityRaman-active vibrational modesspectroscopypentagonal 2 Dpentagonal 2 D materialPentagonal Two-Dimensional LayersPdSe 2