title: Fast and efficient photodetection in nanoscale quantum-dot junctions.
abstract: We report on a photodetector in which colloidal quantum dots directly bridge nanometer-spaced electrodes. Unlike in conventional quantum-dot thin film photodetectors, charge mobility no longer plays a role in our quantum-dot junctions as charge extraction requires only two individual tunnel events. We find an efficient photoconductive gain mechanism with external quantum efficiencies of 38 electrons-per-photon in combination with response times faster than 300 ns. This compact device-architecture may open up new routes for improved photodetector performance in which efficiency and bandwidth do not go at the cost of one another.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA, Delft, The Netherlands. prins@mit.edu
authors.forename: Ferry
authors.initials: F
authors.lastname: Prins
authors.forename: Michele
authors.initials: M
authors.lastname: Buscema
authors.forename: Johannes S
authors.initials: JS
authors.lastname: Seldenthuis
authors.forename: Samir
authors.initials: S
authors.lastname: Etaki
authors.forename: Gilles
authors.initials: G
authors.lastname: Buchs
authors.forename: Maria
authors.initials: M
authors.lastname: Barkelid
authors.forename: Val
authors.initials: V
authors.lastname: Zwiller
authors.forename: Yunan
authors.initials: Y
authors.lastname: Gao
authors.forename: Arjan J
authors.initials: AJ
authors.lastname: Houtepen
authors.forename: Laurens D A
authors.initials: LD
authors.lastname: Siebbeles
authors.forename: Herre S J
authors.initials: HS
authors.lastname: van der Zant
mesh_terms: D003102:Colloids / Q000737:chemistry; D004566:Electrodes; D004583:Electrons; D008027:Light; D018613:Microscopy, Confocal / Q000379:methods; D036103:Nanotechnology / Q000379:methods*; D055095:Optics and Photonics; D010777:Photochemistry / Q000379:methods; D045663:Quantum Dots; D013997:Time Factors
chemical_list: D003102:Colloids