Abstract

Reducing the scale of electronic components to that of nanocrystals or molecules often implies low scalability and complex fabrication. Horizontal architectures generally require costly and sequential processes such as electron beam lithography¹, whilst vertical arrangements using metal evaporation onto molecules or nanocrystals can damage them or cause short circuits². The one-atom-thick material graphene has a number of unique mechanical, electronic and thermodynamic properties that has made it an active field of research since its discovery in 2004³. As efforts are being made to make use of these properties in nanotechnology, its great potential in nanoelectronics and optoelectronics is being revealed and architectures of nanodevices using graphene sheets as electrodes have been proposed[4,5].

We present a novel architecture to investigate electronic transport in colloidal nanocrystals that offers high scalability and flexibility using single-layer graphene as a top electrode. Combining bottom-up and top-down techniques we contacted monolayers of PbS nanocrystals electrically and observed the electron transport in such junctions as a function of potential bias. Preliminary results suggest the occurrence of quantum Coulomb blockade⁶ in the nanocrystals. In this talk I will describe our devices, their fabrication and measurement as well as perspectives for their refinement and development.

[1] D.L. Klein et al., Applied Physics Letters 68, 2574, 1996. [2] H. Haick et al., J. Phys. Chem. C, 111, 2318-2329, 2007. [3] A.K. Geim, Science, 324, 5934, 1530-1534, 2009. [4] J.M. Yuk et al., Nano Lett., 11, 3290–3294, 2011. [5] G. Wang et al., Adv. Matter, 23, 755-760, 2011. [6] U. Meirav and E. B. Foxman, Semicond. Sci. Technol. 11, 255–284, 1996.