Widely tunable alloy composition and crystal structure in catalyst-free InGaAs nanowire arrays grown by selective area molecular beam epitaxy

Journal Article · Mon Feb 01 04:00:00 EST 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4941407· OSTI ID:22489416

Speckbacher, M.; Saller, K.; Morkötter, S.; Xu, X.; Riedl, H.; Abstreiter, G.; Finley, J. J.; Döblinger, M. ^[1]

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1. Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Munich 81377 (Germany)

We delineate the optimized growth parameter space for high-uniformity catalyst-free InGaAs nanowire (NW) arrays on Si over nearly the entire alloy compositional range using selective area molecular beam epitaxy. Under the required high group-V fluxes and V/III ratios, the respective growth windows shift to higher growth temperatures as the Ga-content x(Ga) is tuned from In-rich to Ga-rich InGaAs NWs. Using correlated x-ray diffraction, transmission electron microscopy, and micro-photoluminescence spectroscopy, we identify structural defects to govern luminescence linewidths in In-rich (x(Ga) < 0.4) and Ga-rich (x(Ga) > 0.6) NWs, whereas limitations at intermediate Ga-content (0.4 < x(Ga) < 0.6) are mainly due to compositional inhomogeneities. Most remarkably, the catalyst-free InGaAs NWs exhibit a characteristic transition in crystal structure from wurtzite to zincblende (ZB) dominated phase near x(Ga) ∼ 0.4 that is further reflected in a cross-over from blue-shifted to red-shifted photoluminescence emission relative to the band edge emission of the bulk ZB InGaAs phase.

• OSTI ID: 22489416
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 5 Vol. 108; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
CATALYSTS
CRYSTAL STRUCTURE
GALLIUM ARSENIDES
INDIUM ARSENIDES
LINE WIDTHS
MOLECULAR BEAM EPITAXY
PHOTOLUMINESCENCE
RED SHIFT
SPECTROSCOPY
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
ZINC SULFIDES