Quantitative estimation of density of Bi-induced localized states in GaAs1−xBix grown by molecular beam epitaxy

Yoshimoto, Masahiro; Itoh, Mizuki; Tominaga, Yoriko; Oe, Kunishige

doi:10.1016/j.jcrysgro.2012.12.157

Cited by 33 publications

(31 citation statements)

References 14 publications

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“…It is probable that these activation energies arise from the presence of localised energy levels in the bandgap caused by the clustering of Bi atoms. This result suggests that there is a continuous range of Bi-induced localised states that extend up to 75 meV into the bandgap, which is consistent with the findings of Yoshimoto et al [20].…”

Section: Integrated Emitted Luminescencesupporting

confidence: 92%

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Telecommunication wavelength GaAsBi light emitting diodes

Richards

Hunter

Bastiman

et al. 2016

IET Optoelectronics

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GaAsBi light emitting diodes containing ∼6% Bi are grown on GaAs substrates. Good room-temperature electroluminescence spectra are obtained at current densities as low as 8 Acm − 2. Measurements of the integrated emitted luminescence suggest that there is a continuum of localised Bi states extending up to 75 meV into the bandgap, which is in good agreement with previous photoluminescence studies. X-ray diffraction analysis shows that strain relaxation has probably occurred in the thicker samples grown in this study.

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Section: Integrated Emitted Luminescencesupporting

confidence: 92%

“…The energy of the luminescence peak is thus less than the bandgap energy. As the carrier density (in this case, the injection current) increases, the localised states become filled and the luminescence peak shifts to higher energies [12][13][14][15].…”

Section: Low-temperature Electroluminescencementioning

confidence: 99%

Telecommunication wavelength GaAsBi light emitting diodes

Richards

Hunter

Bastiman

et al. 2016

IET Optoelectronics

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“…Lu et al 41,. as well as other investigators7980, have already reported this type of excitation-dependence for PL signals measured from GaAs 1– x Bi x . Such dependencies are signatures often seen in high-mismatched alloys involving localised states and parallels may be drawn here to the PL dynamics of the GaAsN system8182.…”

Section: Resultssupporting

confidence: 68%

Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

Steele

Lewis

Horvat

et al. 2016

Sci Rep

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Herein we investigate a (001)-oriented GaAs1−xBix/GaAs structure possessing Bi surface droplets capable of catalysing the formation of nanostructures during Bi-rich growth, through the vapour-liquid-solid mechanism. Specifically, self-aligned “nanotracks” are found to exist trailing the Bi droplets on the sample surface. Through cross-sectional high-resolution transmission electron microscopy the nanotracks are revealed to in fact be elevated above surface by the formation of a subsurface planar nanowire, a structure initiated mid-way through the molecular-beam-epitaxy growth and embedded into the epilayer, via epitaxial overgrowth. Electron microscopy studies also yield the morphological, structural, and chemical properties of the nanostructures. Through a combination of Bi determination methods the compositional profile of the film is shown to be graded and inhomogeneous. Furthermore, the coherent and pure zincblende phase property of the film is detailed. Optical characterisation of features on the sample surface is carried out using polarised micro-Raman and micro-photoluminescence spectroscopies. The important light producing properties of the surface nanostructures are investigated through pump intensity-dependent micro-PL measurements, whereby relatively large local inhomogeneities are revealed to exist on the epitaxial surface for important optical parameters. We conclude that such surface effects must be considered when designing and fabricating optical devices based on GaAsBi alloys.

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“…The photoluminescence (PL) emission from molecular beam epitaxy (MBE) grown GaAs 1− x Bi x has been reported to be dominated by localization effects at low temperatures . Similar observations have been previously reported for the dilute nitrides (i.e., GaNAs, GaInNAs) and InGaN material systems .…”

Section: Introductionsupporting

confidence: 73%

Localization effects and band gap of GaAsBi alloys

Mohmad

Bastiman

Hunter

et al. 2014

Phys. Status Solidi B

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The structural and optical properties of GaAs1−xBix alloys for x up to 0.108 have been investigated by high resolution X‐ray diffraction and photoluminescence (PL). At room temperature (RT), the PL intensity of the GaAs0.97Bi0.03 sample was found to be ∼300 times higher than a GaAs control sample grown at the same temperature (400 °C). PL measurements carried out at 10 K show that when excitation power, Pex was increased from 0.11 to 1140 W cm−2, the PL peak energy blue‐shifts by 80 meV while the full‐width‐at‐half‐maximum reduces from 115 to 63 meV. However, the PL peak emission energy becomes independent of the excitation power at RT. The results indicate the presence of localized energy states in the GaAs0.97Bi0.03 sample, which trap carriers at low temperatures and that the majority of the carriers become delocalized at RT. Furthermore, the temperature dependent PL also shows an S‐shape behavior, which is a signature of localization effects. A theoretical model, which was derived by solving a rate equation was employed. The model successfully reproduces the observed S‐shape behavior and the theory fits well with the experimental data. The RT band gap of GaAs1−xBix for x up to 0.108 has been plotted and compared with the literature.

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Quantitative estimation of density of Bi-induced localized states in GaAs1−xBix grown by molecular beam epitaxy

Cited by 33 publications

References 14 publications

Telecommunication wavelength GaAsBi light emitting diodes

Telecommunication wavelength GaAsBi light emitting diodes

Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

Localization effects and band gap of GaAsBi alloys

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