Optimization of AlAs/AlGaAs quantum well heterostructures on on-axis and misoriented GaAs (111)B

F. Herzog, M. Bichler, G. Koblmüller*, S. Prabhu-Gaunkar, W. Zhou, M. Grayson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We report systematic growth optimization of high Al-content AlGaAs, AlAs, and associated modulation-doped quantum well (QW) heterostructures on on-axis and misoriented GaAs (111)B by molecular beam epitaxy. Growth temperatures T G > 690 °C and low As 4 fluxes close to group III-rich growth significantly suppress twin defects in high-Al content AlGaAs on on-axis GaAs (111)B, as quantified by atomic force and transmission electron microscopy as well as x-ray diffraction. Mirror-smooth and defect-free AlAs with pronounced step-flow morphology was further achieved by growth on 2° misoriented GaAs (111)B toward [0 1 1] and [2 1 1 ] orientations. Successful fabrication of modulation-doped AlAs QW structures on these misoriented substrates yielded record electron mobilities (at 1.15 K) in excess of 13 000 cm 2/Vs at sheet carrier densities of 5 × 10 11cm -2.

Original languageEnglish (US)
Article number192106
JournalApplied Physics Letters
Volume100
Issue number19
DOIs
StatePublished - May 7 2012

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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