1. Optimization of AlAs/AlGaAs quantum well heterostructures on on-axis and misoriented GaAs (111)B.
- Author
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Herzog, F., Bichler, M., Koblmüller, G., Prabhu-Gaunkar, S., Zhou, W., and Grayson, M.
- Subjects
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QUANTUM wells , *HETEROSTRUCTURES , *ATOMIC force microscopy , *TRANSMISSION electron microscopy , *X-ray diffraction , *PARTICLES (Nuclear physics) - 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 TG > 690 °C and low As4 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 [formula] and [formula] 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 cm2/Vs at sheet carrier densities of 5 × 1011 cm-2. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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