title: High-Pressure Synthesis and Characterization of β-GeSe-A Six-Membered-Ring Semiconductor in an Uncommon Boat Conformation.
abstract: Two-dimensional materials have significant potential for the development of new devices. Here we report the electronic and structural properties of β-GeSe, a previously unreported polymorph of GeSe, with a unique crystal structure that displays strong two-dimensional structural features. β-GeSe is made at high pressure and temperature and is stable under ambient conditions. We compare it to its structural and electronic relatives α-GeSe and black phosphorus. The β form of GeSe displays a boat conformation for its Ge-Se six-membered ring ("six-ring"), while the previously known α form and black phosphorus display the more common chair conformation for their six-rings. Electronic structure calculations indicate that β-GeSe is a semiconductor, with an approximate bulk band gap of Δ ≈ 0.5 eV, and, in its monolayer form, Δ ≈ 0.9 eV. These values fall between those of α-GeSe and black phosphorus, making β-GeSe a promising candidate for future applications. The resistivity of our β-GeSe crystals measured in-plane is on the order of ρ ≈ 1 Ω·cm, while being essentially temperature independent.
authors.affiliation: Department of Chemistry and ‡Department of Physics, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Fabian O
authors.identifier: 0000-0003-0422-6042
authors.initials: FO
authors.lastname: von Rohr
authors.affiliation: Department of Chemistry and ‡Department of Physics, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Huiwen
authors.initials: H
authors.lastname: Ji
authors.affiliation: Department of Chemistry and ‡Department of Physics, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: F Alexandre
authors.initials: FA
authors.lastname: Cevallos
authors.affiliation: Department of Chemistry and ‡Department of Physics, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Tong
authors.initials: T
authors.lastname: Gao
authors.affiliation: Department of Chemistry and ‡Department of Physics, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: N Phuan
authors.initials: NP
authors.lastname: Ong
authors.affiliation: Department of Chemistry and ‡Department of Physics, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Cava