A Functional 2D Carbon Allotrope Combining Nanoporous Graphene and Biphenylene Segments
Abstract
Abstract The implementation of graphene in semiconductor technology requires bandgap tuning, which can be achieved by chemical doping, geometric confinement in nanoribbons or with the insertion of nanopores and non‐hexagonal rings. The bottom‐up on‐surface synthesis approach in ultra‐high vacuum allows for the synthesis of atomically well‐defined graphene or biphenylene nanoribbons and nanoporous graphene (NPG) structures suitable for device applications. Here, a novel 2D carbon allotrope is synthesized in the form of a functional NPG with periodically spaced biphenylene segments. First, 12‐armchair porous graphene nanoribbons (12‐pGNRs) on Au(111) and Au(788) using 7,10‐dibromo‐1,4‐diphenyl‐triphenylene (DBDT) molecular precursor are grown. Low‐temperature scanning tunneling microscopy/spectroscopy (LT‐STM/STS) and non‐contact atomic force microscopy (nc‐AFM) measurements reveal the presence of high‐quality semiconducting 12‐pGNRs. Thermal annealing of densely packed 12‐pGNRs at 550 °C triggers their lateral fusion into diverse NPG structures featuring either graphene‐type or biphenylene‐type junctions. The structural and electronic properties are again characterized by LT‐STM and nc‐AFM in combination with density functional theory (DFT) calculations. DFT shows that while graphene‐type NPGs are direct bandgap semiconductors, biphenylene‐type NPGs manifest a smaller and indirect bandgap. The NPGs are stable upon oxygen and air exposure, and the nanopores feature a noticeable affinity to carbon monoxide, making them appealing systems for chemical sensors.
Article Details
Authors (15)
Paula Angulo‐Portugal
Centro de Física de Materiales (CFM‐MPC) CSIC‐UPV/EHU Manuel Lardizabal 5 San Sebastian 20018 Spain
Martin Irizar
Department of Polymers and Advanced Materials: Physics, Chemistry and Technology Faculty of Chemistry University of the Basque Country UPV/EHU San Sebastian 20018 Spain
Longfeng Huang
Physics Department E20 TUM School of Natural Sciences Technical University of Munich James‐Franck‐Straße 1 D‐85748 Garching Germany
Mamun Sarker
Department of Chemistry and Nebraska Center for Materials and Nanoscience University of Nebraska − Lincoln Lincoln Nebraska 68588 USA
Mustafa A. Ashoush
Physics Department Faculty of Science Al‐Azhar University Nasr City Cairo E‐11884 Egypt
Zakaria M. Abd El‐Fattah
Physics Department Faculty of Science Al‐Azhar University Nasr City Cairo E‐11884 Egypt
Johannes Barth
Physics Department E20 TUM School of Natural Sciences Technical University of Munich James‐Franck‐Straße 1 D‐85748 Garching Germany
Frederik Schiller
Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, Manuel Lardizábal 5, 20018 San Sebastián, Spain
Afaf El‐Sayed
Centro de Física de Materiales (CFM‐MPC) CSIC‐UPV/EHU Manuel Lardizabal 5 San Sebastian 20018 Spain
Fei Gao
Dimas G. de Oteyza
Donostia International Physics Center (DIPC) Manuel de Lardizabal 4 San Sebastian E‐20018 Spain
Alexander Sinitskii
Aran Garcia‐Lekue
Donostia International Physics Center San Sebastián 20018 Spain
Martina Corso
Centro de Física de Materiales (CFM‐MPC) CSIC‐UPV/EHU Manuel Lardizabal 5 San Sebastian 20018 Spain
Ignacio Piquero‐Zulaica
Centro de Física de Materiales (CFM‐MPC) CSIC‐UPV/EHU Manuel Lardizabal 5 San Sebastian 20018 Spain