標題: How do InAs quantum dots relax when the InAs growth thickness exceeds the dislocation-induced critical thickness?
作者: Chen, J. F.
Lin, Y. C.
Chiang, C. H.
Chen, Ross C. C.
Chen, Y. F.
Wu, Y. H.
Chang, L.
材料科學與工程學系
電子物理學系
Department of Materials Science and Engineering
Department of Electrophysics
公開日期: 1-一月-2012
摘要: A simple critical thickness for generating lattice misfits is insufficient to describe the onset strain relaxation in InAs quantum dots (QDs). A predominant dot family is shown to relieve its strain by In/Ga interdiffusion, rather than by lattice misfits, at the onset of strain relaxation. This argument is based on photoluminescence spectra, which show the emergence of a fine blueshifted transition at the onset of strain relaxation, along with a low-energy transition from a dot family degraded by lattice misfits. From the analysis of the temperature-dependent blueshift and energy separation between the ground and excited-state transitions, the blueshift is attributed to In/Ga interdiffusion. Transmission electron microscopy suggests a relaxation-induced indium migration from the interdiffused dot family to the dislocated dot family. Post-growth thermal annealing can further relieve strain by inducing more In/Ga interdiffusion in the interdiffused dot family and more dislocations in the dislocated dot family. This study explains the co-existence of strong carrier confinement in the QDs and enormous misfit-related traps in the capacitance-voltage spectra, and an elongated QD electron-emission time. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3675519]
URI: http://dx.doi.org/10.1063/1.3675519
http://hdl.handle.net/11536/15323
ISSN: 0021-8979
DOI: 10.1063/1.3675519
期刊: JOURNAL OF APPLIED PHYSICS
Volume: 111
Issue: 1
結束頁: 
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  1. 000299127200046.pdf