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Long-Lived Hot Carriers in III-V Nanowires

Tedeschi, D; De Luca, M; Fonseka, H A; Gao, Q; Mura, F; Tan, Hark Hoe; Rubini, S; Martelli, F; Jagadish, C; Capizzi, M; Polimeni, A

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Heat management mechanisms play a pivotal role in driving the design of nanowire (NW)-based devices. In particular, the rate at which charge carriers cool down after an external excitation is crucial for the efficiency of solar cells, lasers, and high-speed transistors. Here, we investigate the thermalization properties of photogenerated carriers by continuous-wave (cw) photoluminescence (PL) in InP and GaAs NWs. A quantitative analysis of the PL spectra recorded up to 310 K shows that carriers...[Show more]

dc.contributor.authorTedeschi, D
dc.contributor.authorDe Luca, M
dc.contributor.authorFonseka, H A
dc.contributor.authorGao, Q
dc.contributor.authorMura, F
dc.contributor.authorTan, Hark Hoe
dc.contributor.authorRubini, S
dc.contributor.authorMartelli, F
dc.contributor.authorJagadish, C
dc.contributor.authorCapizzi, M
dc.contributor.authorPolimeni, A
dc.date.accessioned2016-08-22T06:10:05Z
dc.date.available2016-08-22T06:10:05Z
dc.identifier.issn1530-6984
dc.identifier.urihttp://hdl.handle.net/1885/107255
dc.description.abstractHeat management mechanisms play a pivotal role in driving the design of nanowire (NW)-based devices. In particular, the rate at which charge carriers cool down after an external excitation is crucial for the efficiency of solar cells, lasers, and high-speed transistors. Here, we investigate the thermalization properties of photogenerated carriers by continuous-wave (cw) photoluminescence (PL) in InP and GaAs NWs. A quantitative analysis of the PL spectra recorded up to 310 K shows that carriers can thermalize at a temperature much higher than that of the lattice. We find that the mismatch between carrier and lattice temperature, ΔT, increases exponentially with lattice temperature and depends inversely on the NW diameter. ΔT is instead independent of other NW characteristics, such as crystal structure (wurtzite vs zincblende), chemical composition (InP vs GaAs), shape (tapered vs columnar NWs), and growth method (vapor-liquid-solid vs selective-area growth). Remarkably, carrier temperatures as high as 500 K are reached at the lattice temperature of 310 K in NWs with ∼70 nm diameter. While a population of nonequilibrium carriers, usually referred to as "hot carriers", is routinely generated by high-power laser pulses and detected by ultrafast spectroscopy, it is quite remarkable that it can be observed in cw PL measurements, when a steady-state population of carriers is established. Time-resolved PL measurements show that even in the thinnest NWs carriers have enough time (∼1 ns) after photoexcitation to interact with phonons and thus to release their excess energy. Nevertheless, the inability of carriers to reach a full thermal equilibrium with the lattice points to inhibited phonon emission primarily caused by the large surface-to-volume ratio of small diameter NWs.
dc.description.sponsorshipM.D.L., D.T., and A.P. acknowledge funding by Sapienza Universitàdi Roma under the “Avvio alla Ricerca 2014”, “Avvio alla Ricerca 2015” and “Ateneo 2013” grants, respectively. A.P. also acknowledges “Awards 2014” by Sapienza Università di Roma. The authors acknowledge F. Mauri and I. Zardo for fruitful discussions. The authors from the Australian National University acknowledge the Australian Research Council for financial support and Australian National Fabrication Facility and Australian Microscopy and Microanalysis Research Facility for providing access to some of the equipment used in this work.
dc.publisherAmerican Chemical Society
dc.rights© 2016 American Chemical Society
dc.sourceNano letters
dc.subjectinp and gaas nanowires
dc.subjecthot carriers
dc.subjectphotoluminescence
dc.subjectwurtzite
dc.subjectzincblende
dc.titleLong-Lived Hot Carriers in III-V Nanowires
dc.typeJournal article
local.identifier.citationvolume16
dc.date.issued2016-05-11
local.publisher.urlhttp://pubs.acs.org/
local.type.statusPublished Version
local.contributor.affiliationFonseka, H. A., Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University
local.contributor.affiliationGao, Q., Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University
local.contributor.affiliationTan, H. H., Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University
local.contributor.affiliationJagadish, C., Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University
local.identifier.essn1530-6992
local.bibliographicCitation.issue5
local.bibliographicCitation.startpage3085
local.bibliographicCitation.lastpage3093
local.identifier.doi10.1021/acs.nanolett.6b00251
CollectionsANU Research Publications

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