Strong electron-electron
(e-e) interactions play an important role in determining the electrical and
optical properties of nanomaterials. Our group uses individually-contacted
carbon nanotubes (CNTs) as a model experimental system to investigate the physics
and applications of these strong interactions. I will discuss: (1) The quantum
efficiency of CNT photodiodes,1 (2) renormalization of the band gap
in semiconducting CNTs,2 (3) the emergence of a Mott insulating
state in metallic CNTs. All three of these topics depend critically on the
strength of e-e interactions which we tune experimentally using dielectric
screening. We also gain new insights by using photocurrent spectroscopy to
precisely identify CNT diameter/chirality, and photocurrent microscopy to quantify
intrinsic region lengths.
1 Aspitarte, McCulley, Minot, “Photocurrent Quantum Yield in Suspended Carbon Nanotube PN Junctions” Nano Letters 16, 5589 (2016)
2 Aspitarte, McCulley, Bertoni, Island, Ostermann, Rontani, Steele & Minot, “Giant modulation of the electronic band gap of carbon nanotubes by dielectric screening”, Scientific Reports 7, 8828 (2017)