Improved performance of GaAsSb/AlGaAs nanowire ensemble Schottky barrier based photodetector via in situ annealing

In this work, we report on the p-i GaAsSb/AlGaAs nanowires (NWs) ensemble device exhibiting good spectral response up to 1.1 m with a high responsivity of 311 A W−1, an external quantum efficiency of 6.1 × 104%, and a detectivity of 1.9 × 1010 Jones at 633 nm. The high responsivity of the NWs has be...

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Bibliographic Details
Published in:Nanotechnology 2019-01, Vol.30 (3), p.34005-034005
Main Authors: Sharma, Manish, Ahmad, Estiak, Dev, Durjoy, Li, Jia, Reynolds, C Lewis, Liu, Yang, Iyer, Shanthi
Format: Article
Language:English
Subjects:
annealing
axial p-i GaAsSb/AlGaAs/GaAs core-shell photodetector
external quantum efficiency
molecular beam epitaxy
suppression of band tail states
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Summary:In this work, we report on the p-i GaAsSb/AlGaAs nanowires (NWs) ensemble device exhibiting good spectral response up to 1.1 m with a high responsivity of 311 A W−1, an external quantum efficiency of 6.1 × 104%, and a detectivity of 1.9 × 1010 Jones at 633 nm. The high responsivity of the NWs has been attributed to in situ post-growth annealing of GaAsSb axial NWs in the ultra-high vacuum. The enabling growth technology is molecular beam epitaxy for the Ga-assisted epitaxial growth of these NWs on Si (111) substrates. Room temperature Raman spectra, as well as temperature dependent micro-photoluminescence peak analysis indicated suppression of band tail states and non-radiative channels due to annealing. A similar improvement in in situ annealed p-i GaAsSb NW ensemble with an AlGaAs passivating shell was inferred from a reduction in the Schottky barrier height as well as the NW resistance compared to the as-grown NW ensemble. These results demonstrate in situ annealing of nanowires to be an effective pathway for improving the optoelectronic properties of the NWs and the device thereof.
ISSN:0957-4484
1361-6528
DOI:10.1088/1361-6528/aae148