Seminar - Dr. Fabian von Rohr (University of Zurich): High-Pressure Synthesis and Characterization of β-GeSe - A Six-Membered-Ring Semiconductor in an Uncommon Boat Conformation

09.03.2018 13:30 – 15:00

Two-dimensional materials such as graphene and transition metal dichalcogenides have shown good potential to act as the basis for future electronics technologies. Similarly, black phosphorus is considered a promising candidate for many applications in electronics and optoelectronics, because, for a small band-gap semiconductor, it displays high mobility charge carriers and can be easily exfoliated [1-5]. While it is the thermodynamically stable phosphorus form, it however oxidizes when exposed to water and oxygen. Therefore, related layered semiconductors are of significant interest.
In this presentation, we report on the electronic and structural properties of β-GeSe [6], 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. Here, we will compare it to its structural and electronic relatives α-GeSe and black phosphorus. The new β form of GeSe displays a boat conformation for its Ge-Se six-membered ring, while the previously known α form, and black phosphorus, display the more common chair conformation for their six-rings. Electronic structure calculations suggest that β-GeSe has a bulk band gap of Δ ≈ 0.5 eV, and, in its monolayer form, Δ ≈ 0.9 eV, between those of α-GeSe and black phosphorus, making it a promising candidate for future applications.

Lieu

Bâtiment: Ecole de Physique

Salle MaNEP

Organisé par

Département de physique de la matière quantique

Intervenant-e-s

Fabian O. Dr. von Rohr , Department of Chemistry, University of Zurich, CH-8057 Zurich, Switzerland

entrée libre

Classement

Catégorie: Séminaire

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