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Optical Properties of GaAs1−xBix/GaAs Quantum Well Structures Grown by Molecular Beam Epitaxy on (100) and (311)B GaAs Substrates

Gunes, M.; Ukelge, M.O.; Donmez, O.; Erol, A.; Gumus, C.; Alghamdi, H.; Galeti, H.V.A.; Henini, M.; Schmidbauer, M.; Hilska, J.; Puustinen, J.; Guina, M.


M. Gunes

M.O. Ukelge

O. Donmez

A. Erol

C. Gumus

H. Alghamdi

H.V.A. Galeti

M. Schmidbauer

J. Hilska

J. Puustinen

M. Guina


In this work, the electronic bandstructure of GaAs1−xBix/GaAs single quantum well (QW) samples grown by molecular beam epitaxy is investigated by photomodulated reflectance (PR) measurements as a function of Bi content (0.0065 ≤ x ≤ 0.0215) and substrate orientation. The Bi composition is determined via simulation of high-resolution x-ray diffraction measurement and is found to be maximized in the 2.15%Bi and 2.1%Bi samples grown on (100) and (311)B GaAs substrates. However, the simulations indicate that the Bi composition is not only limited in the GaAsBi QW layer but extends out of the GaAsBi QW towards the GaAs barrier and forms a GaAsBi epilayer. PR spectra are fitted with the third derivative function form (TDFF) to identify the optical transition energies. We analyze the TDFF results by considering strain-induced modification on the conduction band (CB) and splitting of the valence band (VB) due to its interaction with the localized Bi level and VB interaction. The PR measurements confirm the existence of a GaAsBi epilayer via observed optical transitions that belong to GaAsBi layers with various Bi compositions. It is found that both Bi composition and substrate orientation have strong effects on the PR signal. Comparison between TDFF and calculated optical transition energies provides a bandgap reduction of 92 meV/%Bi and 36 meV/%Bi and an interaction strength of the isolated Bi atoms with host GaAs valence band (C BiM ) of 1.7 eV and 0.9 eV for (100) and (311)B GaAs substrates, respectively.

Journal Article Type Article
Publication Date Nov 13, 2018
Print ISSN 0268-1242
Publisher IOP Publishing
Peer Reviewed Peer Reviewed
Volume 33
Issue 12
Article Number 124015
APA6 Citation Gunes, M., Ukelge, M., Donmez, O., Erol, A., Gumus, C., Alghamdi, H., …Guina, M. (2018). Optical Properties of GaAs1−xBix/GaAs Quantum Well Structures Grown by Molecular Beam Epitaxy on (100) and (311)B GaAs Substrates. Semiconductor Science and Technology, 33(12), doi:10.1088/1361-6641/aaea2e
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