Critical thickness of GaAs/InGaAs and AlGaAs/GaAsP strained quantum wells grown by organometallic chemical vapor deposition |
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Authors: | Daniel C Bertolet Jung-Kuei Hsu Farid Agahi Kei May Lau |
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Affiliation: | (1) Compound Semiconductor Laboratory, Department of Electrical and Computer Engineering, University of Massachusetts, 01003 Amherst, MA |
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Abstract: | In this paper we describe a study of strained quantum wells (QWs) as a means to experimentally observe the critical thickness
(h
c) for the formation of interfacial misfit dislocations. Two material systems were investigated: GaAs/In0.11Ga0.89As, in which the QW layers are under biaxialcompression, and Al0.35Ga0.65As/GaAs0.82P0.18, in which the QW layers are under biaxialtension. Samples were grown by atmospheric pressure organometallic chemical vapor deposition, and characterized by low-temperature
photoluminescence (PL), x-ray diffraction, optical microscopy, and Hall measurements. For both material systems, the observed
onset of dislocation formation agrees well with the force-balance model assuming a double-kink mechanism. However, overall
results indicate that the relaxation is inhomogeneous. Annealing at 800–850° C had no significant effect on the PL spectra,
signifying that even layers that have exceededh
c and have undergone partial relaxation are thermodynamically stable against further dislocation propagation. |
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Keywords: | GaAs/InGaAs critical thickness strained quantum wells |
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