Optical study of strained and relaxed epitaxial InxGa 1-xAs on GaAs

L. C. Andreani, D. De Nova, S. Di Lernia, M. Geddo, G. Guizzetti, M. Patrini, C. Bocchi, A. Bosacchi, C. Ferrari, S. Franchi

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Photoreflectance (PR) at different temperatures and spectroellipsometry (SE) at room temperature were used to study, in a systematic and complementary way, the optical response of a series of strained and relaxed In xGa1-xAs (x<0.15) epilayers. All the samples were grown by molecular-beam epitaxy on GaAs, both with and without a GaAs cap layer, which in the thinnest samples determines a single-quantum-well configuration. The effects of the strain on the optical structures E0, E 1, and E11 observed in the 1.2-3.3 eV photon-energy range were analyzed by fitting standard critical points (CP) line shapes to the PR and SE spectra. The CP experimental energies versus x were compared with the relations obtained in the framework of the elastic strain theory and, in the quantum-well structures, of the envelope-function scheme. The excellent agreement between experiment and theory allowed us to determine, independently and only by optical techniques, the strain ε and the composition x values, which compare well with those measured by x-ray diffraction. Additional information concerning the critical thickness for the pseudomorphic growth and the residual strain in quasirelaxed layers was achieved.

Original languageEnglish
Pages (from-to)6745-6751
Number of pages7
JournalJournal of Applied Physics
Issue number11
Publication statusPublished - Dec 1 1995

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Andreani, L. C., De Nova, D., Di Lernia, S., Geddo, M., Guizzetti, G., Patrini, M., Bocchi, C., Bosacchi, A., Ferrari, C., & Franchi, S. (1995). Optical study of strained and relaxed epitaxial InxGa 1-xAs on GaAs. Journal of Applied Physics, 78(11), 6745-6751. https://doi.org/10.1063/1.360498