| 1. |
- Al-Abri, Ruqaiya, et al.
(author)
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Sub-Picosecond Carrier Dynamics Explored using Automated High-Throughput Studies of Doping Inhomogeneity within a Bayesian Framework
- 2023
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In: Small. - 1613-6810. ; 19:33
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Journal article (peer-reviewed)abstract
- Bottom–up production of semiconductor nanomaterials is often accompanied by inhomogeneity resulting in a spread in electronic properties which may be influenced by the nanoparticle geometry, crystal quality, stoichiometry, or doping. Using photoluminescence spectroscopy of a population of more than 11 000 individual zinc-doped gallium arsenide nanowires, inhomogeneity is revealed in, and correlation between doping and nanowire diameter by use of a Bayesian statistical approach. Recombination of hot-carriers is shown to be responsible for the photoluminescence lineshape; by exploiting lifetime variation across the population, hot-carrier dynamics is revealed at the sub-picosecond timescale showing interband electronic dynamics. High-throughput spectroscopy together with a Bayesian approach are shown to provide unique insight in an inhomogeneous nanomaterial population, and can reveal electronic dynamics otherwise requiring complex pump-probe experiments in highly non-equilibrium conditions.
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| 2. |
- Persson, Axel R., et al.
(author)
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Electron Tomography Reveals the Droplet Covered Surface Structure of Nanowires Grown by Aerotaxy
- 2018
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In: Small. - : Wiley. - 1613-6810. ; 14:33
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Journal article (peer-reviewed)abstract
- For the purpose of functionalizing III-V semiconductor nanowires using n-doping, Sn-doped GaAs zincblende nanowires are produced, using the growth method of Aerotaxy. The growth conditions used are such that Ga droplets, formed on the nanowire surface, increase in number and concentrations when the Sn-precursor concentration is increased. Droplet-covered wires grown with varying Sn concentrations are analyzed by transmission electron microscopy and electron tomography, which together establish the positioning of the droplets to be preferentially on {−111}B facets. These facets have the same polarity as the main wire growth direction, [−1−1−1]B. This means that the generated Ga particles can form nucleation sites for possible nanowire branch growth. The concept of azimuthal mapping is introduced as a useful tool for nanowire surface visualization and evaluation. It is demonstrated here that electron tomography is useful in revealing both the surface and internal morphologies of the nanowires, opening up for applications in the analysis of more structurally complicated systems like radially asymmetrical nanowires. The analysis also gives a further understanding of the limits of the dopants which can be used for Aerotaxy nanowires.
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