Analysis of strain relaxation in GaAsInGaAsGaAs structures by spectroscopy of relaxation-induced states

Jenn-Fang Chen*, C. H. Chiang, P. C. Hsieh, J. S. Wang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Strain relaxation in GaAs In0.2 Ga0.8 AsGaAs structures is investigated by analyzing relaxation-induced traps. Strain relaxation is shown to cause carrier depletion by the induction of a 0.53 eV trap in the top GaAs layer, a 0.13 eV trap in the InGaAs layer, and a 0.33 eV trap in the neighboring lower GaAs layer. The 0.53 eV trap which exhibits a logarithmic function of transient capacitance is attributed to threading dislocations. The 0.33 eV trap exhibits an exponential transient capacitance, suggesting a GaAs point defect as its origin. Given its activation energy, it is assigned to the EL6 in GaAs, commonly considered to be Asi - VGa complexes. This trap and the 0.13 eV trap are regarded as the same, since their energy difference is comparable to the optically determined conduction-band offset. The spatial location of this trap correlates with that of misfit dislocations. Accordingly, the production of this trap is determined from the mechanism of strain relaxation. A likely mode of strain relaxation is deduced from the locations of these traps.

Original languageEnglish
Article number033702
JournalJournal of Applied Physics
Volume101
Issue number3
DOIs
StatePublished - 26 Feb 2007

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