Carrier distribution and relaxation-induced defects of InAs/GaAs quantum dots

J. S. Wang*, Jenn-Fang Chen, J. L. Huang, P. Y. Wang, X. J. Guo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

The carrier distribution and defects have been investigated in InAs/GaAs quantum dots by cross-sectional transmission electron microscopy (XTEM), capacitance-voltage, and deep level transient spectroscopy. Carrier confinement is found for 1.1-and 2.3-monolayer-(ML)-thick InAs samples. For 2.3 ML sample, XTEM images show the presence of defect-free self-assembled quantum dots. With further increase of the InAs thickness to 3.4 ML, significant carrier depletion caused by the relaxation is observed. In contrast to 1.1 and 2.3 ML samples in which no traps are detected, two broad traps and three discrete traps at 0.54, 0.40, and 0.34 eV are observed in 3.4 ML sample. The traps at 0.54 and 0.34 eV are found to be similar to the traps observed in relaxed In0.2Ga0.8As/GaAs single quantum well structures. By comparing with the XTEM images, the trap at 0.54 eV is identified to be the relaxation-induced dislocation trap in the GaAs layer.

Original languageEnglish
Pages (from-to)3027-3029
Number of pages3
JournalApplied Physics Letters
Volume77
Issue number19
DOIs
StatePublished - 6 Nov 2000

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