Improving electron mobility in InAs quantum wells on GaAs by removing bunched surface steps generated in strain relaxation
Abstract
The effect of surface smoothing in the heteroepitaxy of InAs quantum wells on GaAs(001) is investigated using transmission electron microscopy. While the stress fields cause the relaxation of the lattice in the growth of the (Al,In)As buffer layer, step bunching occurs with creating wide flat terraces in the process of forming the cross-hatch pattern. The bunched steps lower the electron mobility in the quantum wells considerably when the GaAs substrates are used instead of InP substrates due to their pronounced presence resulting from the larger lattice mismatch. The enhancement of the surface migration of adatoms in growth interruptions is shown to annihilate the steps, giving rise to an improvement of the mobility due to the suppression of the interface roughness scattering. With the introduction of the surface smoothing, GaAs substrates thus replace InP substrates as a less-expensive and superior alternative.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (8)
A. Aleksandrova
Department of Physics, Humboldt-Universität zu Berlin 1 , Newtonstraße 15, 12489 Berlin,
E. Paysen
Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V 3 ., Hausvogteiplatz 5-7, 10117 Berlin,
C. Golz
Department of Physics, Humboldt-Universität zu Berlin 1 , Newtonstraße 15, 12489 Berlin,
K. Biermann
Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V 3 ., Hausvogteiplatz 5-7, 10117 Berlin,
A. Trampert
Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V 3 ., Hausvogteiplatz 5-7, 10117 Berlin,
H. Weidlich
Institut Kurz GmbH 2 , Stöckheimer Weg 1, 50829 Cologne,
W. T. Masselink
Department of Physics, Humboldt-Universität zu Berlin 1 , Newtonstraße 15, 12489 Berlin,
Y. Takagaki
Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V 3 ., Hausvogteiplatz 5-7, 10117 Berlin,