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Aerotaxy is a unique technique to grow nanowires in a continuous gas flow without a substrate[1]. Controlled dopant levels have been demonstrated in this technique to high concentrations[2]. Recently, we have used high-throughput techniques to reveal the relationship between internal quantum efficiency and Zn-doping in GaAs[3], a crucial parameter to determine the nanowire performance.
In our study, we calculate the internal quantum efficiency of aerotaxy-grown nanowires with Zn dopant levels spanning (1019-1020 cm-3). By measuring photoluminescence from >1000 nanowires, we use intrinsic spread in doping level to study interwire inhomogeneities. The active hole density in nanowires with high Zn concentration is sub-linear with doping, indicating that a high Zn concentration may lead to Zn agglomeration which hence reduces the number of holes produced per Zn atom. This correlates with a reduction in material crystallinity observed via Raman spectroscopy.
By correlating the emission intensity with the hole concentration, an expected increase of the efficiency is observed with doping. However, further increases in doping lead to Auger recombination which results in reducing efficiency.
High-throughput measurement is an important method to probe the interwire inhomogeneity in nanowires produced by aerotaxy. Relating functional parameters with doping provides deep understanding, as well as a route to optimize performance in many optoelectronic applications namely lasing, LEDs, and photodetection.
[1] Heurlin, M.; Magnusson, M.; Lindgren, D., et al. Continuous gas-phase synthesis of nanowires with tunable properties. Nature 2012, 492, 90-94
[2] Yang, F.; Messing, M. E.; Mergenthaler, K., et al. Zn-doping of GaAs nanowires grown by Aerotaxy. Journal of Crystal Growth 2015, 414, 181-186
[3] Alanis, J.; Lysevych, M.; Burgess, T., et al. Optical Study of p-Doping in GaAs Nanowires for Low-Threshold and High-Yield Lasing. Nanoletters 2018, 19, 362-368
| Speaker Country | United Kingdom |
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