title: Multiple exciton generation induced enhancement of the photoresponse of pulsed-laser-ablation synthesized single-wall-carbon-nanotube/PbS-quantum-dots nanohybrids.
abstract: The pulsed laser deposition method was used to decorate appropriately single wall carbon nanotubes (SWCNTs) with PbS quantum dots (QDs), leading to the formation of a novel class of SWCNTs/PbS-QDs nanohybrids (NHs), without resorting to any ligand engineering and/or surface functionalization. The number of laser ablation pulses (NLp) was used to control the average size of the PbS-QDs and their coverage on the SWCNTs' surface. Photoconductive (PC) devices fabricated from these SWCNTs/PbS-QDs NHs have shown a significantly enhanced photoresponse, which is found to be PbS-QD size dependent. Wavelength-resolved photocurrent measurements revealed a strong photoconductivity of the NHs in the UV-visible region, which is shown to be due to multiple exciton generation (MEG) in the PbS-QDs. For the 6.5 nm-diameter PbS-QDs (with a bandgap (Eg) = 0.86 eV), the MEG contribution of the NHs based PC devices was shown to lead to a normalized internal quantum efficiency in excess of 300% for photon energies ≥4.5Eg. While the lowest MEG threshold in our NHs based PC devices is found to be of ~2.5Eg, the MEG efficiency reaches values as high as 0.9 ± 0.1.
authors.affiliation: Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650, Blvd. Lionel-Boulet, Varennes, Qc, J3X-1S2, Canada.
authors.forename: Ibrahima
authors.initials: I
authors.lastname: Ka
authors.affiliation: Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650, Blvd. Lionel-Boulet, Varennes, Qc, J3X-1S2, Canada.
authors.forename: Vincent
authors.initials: V
authors.lastname: Le Borgne
authors.affiliation: Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano, 380-8553, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Fujisawa
authors.affiliation: Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano, 380-8553, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano, 380-8553, Japan.|School of Polymer Science and Engineering, Chonnam National University, 77 Yonggong-ro, Buk-gu, Gwangju, 500-757, South Korea.
authors.forename: Yoong Ahm
authors.initials: YA
authors.lastname: Kim
authors.affiliation: Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano, 380-8553, Japan.
authors.forename: Morinobu
authors.initials: M
authors.lastname: Endo
authors.affiliation: Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650, Blvd. Lionel-Boulet, Varennes, Qc, J3X-1S2, Canada.
authors.forename: Dongling
authors.initials: D
authors.lastname: Ma
authors.affiliation: Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650, Blvd. Lionel-Boulet, Varennes, Qc, J3X-1S2, Canada.
authors.forename: My Ali
authors.initials: MA
authors.lastname: El Khakani
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