Title: Strain relaxation in InAs self-assembled quantum dots induced by a high N incorporation
Authors: Chen, J. F.
Yang, C. H.
Wu, Y. H.
Chang, L.
Chi, J. Y.
Department of Materials Science and Engineering
Department of Electrophysics
Keywords: deep levels;defect states;III-V semiconductors;indium compounds;internal stresses;nitrogen;self-assembly;semiconductor quantum dots;stress relaxation;transmission electron microscopy
Issue Date: 15-Nov-2008
Abstract: The effect of a high N incorporation in self-assembled InAs quantum dots (QDs) is investigated by analyzing the electronic and structural properties around QD region. Capacitance-voltage profiling and admittance spectroscopy shows that N incorporation into the InAs QD layer leads to drastic carrier depletion in the QD layer and neighboring GaAs layers due to the formation of a deep defect state at 0.34-0.41 eV. The signature of this defect state is similar to those defects observed in strain relaxed QDs or InGaAs/GaAs quantum wells when the InAs deposition thickness exceeds a critical thickness. Accordingly, the N incorporation might result in strain relaxation either by increasing localized strain or by inducing composition inhomogeneities, which provide nucleation sources for strain relaxation. The argument of strain relaxation is supported by transmission electron microscopy that reveals lattice misfits at the QD layer and neighboring GaAs layers.
URI: http://dx.doi.org/10.1063/1.3028235
ISSN: 0021-8979
DOI: 10.1063/1.3028235
Volume: 104
Issue: 10
End Page: 
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