Optical far-field extinction of a single GaAs nanowire towards in situ size control of aerotaxy nanowire growth

dc.contributorAalto Universityen
dc.contributor.authorChen, Yangen_US
dc.contributor.authorAnttu, Nicklasen_US
dc.contributor.authorSivakumar, Sudhakaren_US
dc.contributor.authorGompou, Elenien_US
dc.contributor.authorMagnusson, Martinen_US
dc.contributor.departmentDepartment of Electronics and Nanoengineeringen
dc.contributor.groupauthorHarri Lipsanen Groupen
dc.contributor.organizationLund Universityen_US
dc.description.abstractA substrate-free approach of semiconductor nanowire growth has been achieved by the aerotaxy technique previously. In this work, we propose an in situ method to monitor the size of nanowires through non-destructive optical-extinction measurements. Our work aims to build a theoretical look-up database of extinction spectra for a single nanowire of varying dimensions. We describe the origin of possible peaks in the spectra, for example due to nanowire-length dependent Fabry–Perot resonances and nanowire-diameter dependent TM and TE mode resonances. Furthermore, we show that the Au catalyst on top of the nanowire can be ignored in the simulations when the volume of the nanowire is an order of magnitude larger than that of the Au catalyst and the diameter is small compared to the incident wavelength. For the calculation of the extinction spectra, we use the finite element method, the discrete dipole approximation and the Mie theory. To compare with experimental measurements of randomly oriented nanowires, we perform an averaging over nanowire orientation for the modeled results. However, in the experiments, nanowires are accumulating on the quartz window of the measurement setup, which leads to increasing uncertainty in the comparison with the experimental extinction spectra. This uncertainty can be eliminated by considering both a sparse and a dense collection of nanowires on the quartz window in the optical simulations. Finally, we create a database of extinction spectra for a GaAs nanowire of varying diameters and lengths. This database can be used to estimate the diameter and the length of the nanowires by comparing the position of a peak and the peak-to-shoulder difference in the extinction spectrum. Possible tapering of nanowires can be monitored through the appearance of an additional peak at a wavelength of 700–800 nm.en
dc.description.versionPeer revieweden
dc.identifier.citationChen, Y, Anttu, N, Sivakumar, S, Gompou, E & Magnusson, M 2020, ' Optical far-field extinction of a single GaAs nanowire towards in situ size control of aerotaxy nanowire growth ', Nanotechnology, vol. 31, no. 13, 134001 . https://doi.org/10.1088/1361-6528/ab5fe4en
dc.identifier.otherPURE UUID: 4e8f6ce0-0012-47a0-bb0d-8121386c37e6en_US
dc.identifier.otherPURE ITEMURL: https://research.aalto.fi/en/publications/4e8f6ce0-0012-47a0-bb0d-8121386c37e6en_US
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dc.relation.ispartofseriesVolume 31en
dc.subject.keywordsemiconductor nanowireen_US
dc.subject.keywordlight scatteringen_US
dc.subject.keywordaerotaxy growthen_US
dc.titleOptical far-field extinction of a single GaAs nanowire towards in situ size control of aerotaxy nanowire growthen
dc.typeA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessäfi