title: Transport in a Single Self-Doped Nanocrystal.
abstract: Addressing the optical properties of a single nanoparticle in the infrared is particularly challenging, thus alternative methods for characterizing the conductance spectrum of nanoparticles in this spectral range need to be developed. Here we describe an efficient method of fabricating single nanoparticle tunnel junctions on a chip circuit. We apply this method to narrow band gap nanoparticles of HgSe, which band structure combines the inverted character of the bulk semimetal with quantum confinement and self-doping. Upon tuning the gate bias, measurement reveals the presence of two energy gaps in the spectrum. The wider gap results from the interband gap, while the narrower gap results from intraband transitions. The observation of the latter near zero gate voltage confirms the doped character of the nanoparticle at the single particle level, which is in full agreement with the ensemble optical and transport measurements. Finally we probe the phototransport within a single quantum dot and demonstrate a large photogain mechanism resulting from photogating.
authors.affiliation: ESPCI-ParisTech, PSL Research University, UPMC Université Paris 06, LPEM, CNRS , 10 rue Vauquelin, Paris Cedex 5 F-75231, France.
authors.forename: Hongyue
authors.initials: H
authors.lastname: Wang
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris , Paris F-75005, France.
authors.forename: Emmanuel
authors.identifier: 0000-0003-2582-1422
authors.initials: E
authors.lastname: Lhuillier
authors.affiliation: ESPCI-ParisTech, PSL Research University, UPMC Université Paris 06, LPEM, CNRS , 10 rue Vauquelin, Paris Cedex 5 F-75231, France.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yu
authors.affiliation: ESPCI-ParisTech, PSL Research University, UPMC Université Paris 06, LPEM, CNRS , 10 rue Vauquelin, Paris Cedex 5 F-75231, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Zimmers
authors.affiliation: ESPCI-ParisTech, PSL Research University, UPMC Université Paris 06, LPEM, CNRS , 10 rue Vauquelin, Paris Cedex 5 F-75231, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Dubertret
authors.affiliation: Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud, Université Paris-Saclay , C2N - Marcoussis, Marcoussis 91460, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Ulysse
authors.affiliation: ESPCI-ParisTech, PSL Research University, UPMC Université Paris 06, LPEM, CNRS , 10 rue Vauquelin, Paris Cedex 5 F-75231, France.
authors.forename: Hervé
authors.identifier: 0000-0002-2061-3715
authors.initials: H
authors.lastname: Aubin
keywords: interband and intraband transitions; photoconductance; quantum dot; tunnel spectroscopy