Effect of heteroepitaxial growth on LT-GaAs: ultrafast optical properties
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comunitat-uji-handle2:10234/2507
comunitat-uji-handle3:10234/6973
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Title
Effect of heteroepitaxial growth on LT-GaAs: ultrafast optical propertiesAuthor (s)
Date
2021-06-16Publisher
IOP PublishingISSN
0953-8984; 1361-648XBibliographic citation
AFALLA, Jessica, et al. Effect of heteroepitaxial growth on LT-GaAs: ultrafast optical properties. Journal of Physics: Condensed Matter, 2021, vol. 33, no 31, p. 315704.Type
info:eu-repo/semantics/articleVersion
info:eu-repo/semantics/acceptedVersionSubject
Abstract
Epitaxial low temperature grown GaAs (LT-GaAs) on silicon (LT-GaAs/Si) has the potential for terahertz (THz) photoconductive antenna applications. However, crystalline, optical and electrical properties of heteroepi ... [+]
Epitaxial low temperature grown GaAs (LT-GaAs) on silicon (LT-GaAs/Si) has the potential for terahertz (THz) photoconductive antenna applications. However, crystalline, optical and electrical properties of heteroepitaxial grown LT-GaAs/Si can be very different from those grown on semi-insulating GaAs substrates ('reference'). In this study, we investigate optical properties of an epitaxial grown LT-GaAs/Si sample, compared to a reference grown under the same substrate temperature, and with the same layer thickness. Anti-phase domains and some crystal misorientation are present in the LT-GaAs/Si. From coherent phonon spectroscopy, the intrinsic carrier densities are estimated to be 1015 cm−3 for either sample. Strong plasmon damping is also observed. Carrier dynamics, measured by time-resolved THz spectroscopy at high excitation fluence, reveals markedly different responses between samples. Below saturation, both samples exhibit the desired fast response. Under optical fluences ⩾54 μJ cm−2, the reference LT-GaAs layer shows saturation of electron trapping states leading to non-exponential behavior, but the LT-GaAs/Si maintains a double exponential decay. The difference is attributed to the formation of As–As and Ga–Ga bonds during the heteroepitaxial growth of LT-GaAs/Si, effectively leading to a much lower density of As-related electron traps. [-]
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Jessica Afalla et al 2021 J. Phys.: Condens. Matter 33 315704Related data
https://doi.org/10.1088/1361-648X/ac04ccRights
© 2021 IOP Publishing Ltd Printed in the UK
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info:eu-repo/semantics/openAccess
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