Quantum dots embedded in graphene nanoribbons by chemical substitution

Bottom-up chemical reactions of selected molecular precursors on a gold surface can produce high quality graphene nanoribbons (GNRs). Here, we report on the formation of quantum dots embedded in an armchair GNR by substitutional inclusion of pairs of boron atoms into the GNR backbone. The boron inclusion is achieved through the addition of a small amount of boron substituted precursors during the formation of pristine GNRs. In the pristine region between two boron pairs, the nanoribbons show a discretization of their valence band into confined modes compatible with a Fabry–Perot resonator. Transport simulations of the scattering properties of the boron pairs reveal that they selectively confine the first valence band of the pristine ribbon while allowing an efficient electron transmission of the second one. Such band-dependent electron scattering stems from the symmetry matching between the electronic wave functions of the states from the pristine nanoribbons and those localized at the boron pairs.This work was supported by FP7 FET-ICT “Planar Atomic and Molecular Scale devices” (PAMS) project (funded by the European Commission under contract No. 610446), by the Spanish Ministerio de Economia y Competitividad (MINECO) (Grants No. MAT2013-46593-C6) and the Basque Government (Dep. de Educacion and UPV/EHU, Grant No. IT-756-13, and Dep. Industry, Grant PI_2015_1_42), by the Japan Science and Technology Agency (JST) “Precursory Research for Embryonic Science and Technology (PRESTO)” for a project of “Molecular technology and creation of new function”, by JSPS KAKENHI Grant No. 15K21765, by the Swiss National Science Foundation and by the Swiss Nanoscience Institute (SNI).Peer Reviewe