Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 19: Quantum dots and wires: Transport properties

HL 19.12: Talk

Tuesday, March 13, 2018, 12:30–12:45, A 151

Coulomb staircase in CMOS-compatible large-area junctions of self-assembled quantum dots using graphene — Hippolyte P.A.G. Astier¹, Joel M. Fruhman¹, Lissa Eyre¹, Bruno Ehrler⁴, Marcus Boehm¹, Piran R. Kidambi², Ugo Sassi², Domenico De Fazio², Jonathan P. Griffiths¹, Alexander Robson³, Benjamin J. Robinson³, Stephan Hofmann², Andrea C. Ferrari², and •Christopher J.B. Ford¹ — ¹Cavendish Laboratory, JJ Thomson Av. CB3 0HE, Cambridge, UK — ²Cambridge Graphene Centre, 9 JJ Thomson Av. CB3 0FA, Cambridge, UK — ³Department of Physics, University of Lancaster, Lancaster LA1 4YB, UK — ⁴Center for Nanophotonics, AMOLF, Science Park 104, 1098 XG, Amsterdam, The Netherlands

Nanomaterial and molecular electronics suffers from unscalable and complex fabrication. Here, we use graphene to make arrays of ∼1µm² junctions contacting self-assembled monolayers of PbS quantum dots (QDs) to obtain films with zero-dimensional transport characteristics. Our junctions exhibit Coulomb blockade and staircases with a yield above 40% before optimisation, thus demonstrating single-electron effects in a robust and scalable architecture. Electron-beam lithography can reduce contact areas to nanometre sizes, enabling a statistical comparison between junctions with a range of QD numbers. Topographical imaging combining atomic force microscopy (AFM) and ultrasonic force microscopy (UFM) allows us to investigate the conduction parameters in these complex films in relation to their mechanical aspect.