Optical Properties of Closely Coupled Dilute Nitride Mid-Infrared InNSb Quantum Dots (original) (raw)
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Self-assembled InAs/GaAs quantum dots (QD) are extensively studied for their potential application in optoelectronic devices. In this paper, we report the influence of QD growth rate on the optical properties of InAs/GaAs QDs under their exposure to a Nitrogen plasma. The samples under study are grown by molecular beam epitaxy and characterized by photoluminescence spectroscopy (PL). For capped unnitrided QDs, the increase in InAs growth rate is accompanied by an increase in PL emission energy and PL full width at half maximum (FWHM). Under nitridation, it was found that the incorporation of Nitrogen (N) strongly affected the QD emission and showed a significant redshift of the photoluminescence peak emission. In addition, PL FWHM decreases as the growth rate of InAs increases. The temperature dependence of the PL peak energy of the unnitrided and nitrided QDs exhibits a V shape associated to the carrier localization phenomenon induced by the spatially fluctuating potential. This be...
Journal of Crystal Growth, 2004
Self-assembled InAs quantum dots (QDs) with In 0.15 Ga 0.85 As were grown by a molecular beam epitaxy and their optical properties were investigated by photoluminescence (PL) spectroscopy. For InAs QDs inserted in an asymmetric In 0.15 Ga 0.85 As quantum well, the emission peak position of QDs is 1.30 mm (0.953 eV) with narrower PL linewidth and larger energy-level spacing between the ground states and the first excited states compared to those of QDs embedded in a GaAs matrix. While the room temperature PL yield for InAs QDs in a GaAs matrix was reduced by 1/99 from that measured at 18 K, the reduction in PL yield for InAs QDs, grown on a 1 nm In 0.15 Ga 0.85 As layer, with a 6 nm In 0.15 Ga 0.85 As overgrowth layer was only 1/27. Also, using the In 0.15 Ga 0.85 As overgrowth layer significantly reduced the temperature sensitivity of the peak energy for InAs QDs. The relatively better temperature PL characteristics of the QDs with In 0.15 Ga 0.85 As, as well as the ability to control the emission peak position and the energy-level spacing are interesting and important for device applications. r
Dilute nitride InNP quantum dots: Growth and photoluminescence mechanism
Self-assembled dilute nitride InNP quantum dots (QDs) in GaP matrix grown under the Stranski-Krastanov mode by gas-source molecular beam epitaxy are studied. The N-related localized states inside the InNP QDs provide a spatially direct recombination channel, in contrast to the spatially indirect channel through the strained In(N)P QDs/GaP interface states. The N incorporation into InP QDs therefore causes a blueshift and double-peak features in photoluminescence, which are not observed in other dilute nitride materials.
Optical properties of self-assembled InAs quantum dots on high-index GaAs substrates
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In this work we have studied the optical properties of InAs quantum dots (QDs) grown by molecular-beam epitaxy on GaAs (211)A, on (n11)A/B (where n is 1, 5 and 7), and on reference (100) substrates. Investigation of orientation and polarity effects by means of photoluminescence (PL) are also presented. The PL spectra reveal interesting differences in amplitude, integral luminescence, peak position and peak shape. The PL temperature dependence indicates an additional lateral confinement on (100), (n11)B, (211)A and (111)A surfaces. Our results also show an enhancement of the QD onset thermal quenching energy by a factor of ∼ 3 for these orientations. In contrast, the structures grown on (711)A and (511)A surfaces do not exhibit QD formation.
Investigations of InSb-based quantum dots grown by molecular-beam epitaxy
(2007) Physica Status Solidi (C) Current Topics in Solid State Physics, 4 (5), pp. 1743-1746.
InSb quantum dots (QDs) have been grown by molecular-beam epitaxy (MBE) on GaSb substrates. Typical MBE growth conditions lead to a low density (∼ 109 cm-2) of large islands which are dislocated. Insertion of a thin InAs nucleation layer increases the QDs density by one order of magnitude which is interpreted in terms of differing In-to-group-V binding energies. Finally, we show that a high density (∼ 7 × 1010 cm-2) of small coherent QDs can be grown by using a two-steps procedure. Photoluminescence near 3.5 μm is demonstrated.
Research Journal of Applied Sciences, Engineering and Technology, 2013
This study presents self-assembled quantum dots structures made on GaAs substrate. The samples were grown by Molecular Beam Epitaxy (MBE) in the Stranski-Krastanow (SK) growth mode. Two types of quantum dots structures are performed under different growth conditions and are compared: the first type is composed of two structures with InAs quantum dots encapsulated with (Ga, In) (N, As) and the second one with boxes wrapped with InGaAs. The influence of encapsulation of quantum dots is highlighted and as already shown, the redshift of emission wavelength depends on nitrogen doping. Further investigations are done through the incorporation of indium and nitrogen in the quantum dots structures in order to understand their optimal doping level on electrical and optical properties. The effects of temperature, an important growth parameter, are examined through images of nanostructures obtained by Atomic Force Microscopy (AFM) and Scanning Electronic Microscopy (SEM) techniques.
Influence of GaAsBi Matrix on Optical and Structural Properties of InAs Quantum Dots
Nanoscale research letters, 2016
InAs/GaAsBi dot-in-well structures were fabricated using gas-source molecular beam epitaxy and investigated for its optical and structural properties. GaAsBi-strained buffer layer and strain reduction layer are both effective to extend the photoluminescence (PL) emission wavelength of InAs quantum dot (QD). In addition, a remarkable PL intensity enhancement is also obtained compared with low-temperature-grown GaAs-capped InAs QD sample. The GaAsBi matrix also preserves the shape of InAs QDs and leads to increase the activation energy for nonradiative recombination process at low temperature. Lower density and larger size of InAs QDs are obtained on the GaAsBi surface compared with the QDs grown on GaAs surface.