Effect of GaAs spacer layer thickness on optical properties of multi-stacked InAs/GaAs quantum dots

Mohanta, Antaryami; Jang, Der-Jun; Wang, Fuyu; Wang, J.S.

doi:10.1016/j.jlumin.2016.01.011

Cited by 5 publications

(2 citation statements)

References 29 publications

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“…Furthermore, in very-closely stacked BQD studies, a subtle abnormal blueshift of emission (<0.1 eV) was observed by decreasing the GaAs spacer, and was attributed to the formation of the structural defects around the QDs due to the large strain [32,33]. It was also suggested that the strain induced by decreasing the GaAs spacer thickness may alter the dominant recombination pathway from heavy holes to light holes, leading to an apparent significant PL blueshift [34]. At the same time, decreasing GaAs spacer thickness would also increase the size of the BQDs.…”

Section: Discussionmentioning

confidence: 99%

Anomalous photoluminescence of InAs surface quantum dots: intensity enhancement and strain control by underlying quantum dots

2022

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Strain control and photoluminescence (PL) enhancement of InAs surface quantum dots (SQDs), exposed to ambient conditions, have been achieved by introducing underlying buried quantum dots (BQDs). The PL wavelength has been tuned from 1270 to as long as 1780 nm, redshifted as the size of the SQDs is reduced. This is in strong contrast to standard QDs, in which blueshift is observed from smaller QDs following basic quantum mechanics. Here, smaller SQDs, both in height and base area, as observed by atomic force microscopy, were obtained with wider GaAs spacer thickness between the SQDs and BQDs. The result strongly suggests that strain and related effects dominate the electronic properties of the SQDs rather than their size, and that a change in the complex strain field occurs through the spacer. The underlying BQDs also serve as effective carrier reservoirs. A PL intensity enhancement of 17 fold was observed as the GaAs spacer thickness was reduced from 150 to 10 nm. A large portion of the photoexcited carriers is initially captured and stored in the BQDs. When sufficient carriers are transferred to fill non-radiative surface states, the excess may be transferred to the SQDs enhancing the luminescence.

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Section: Discussionmentioning

confidence: 99%

Anomalous photoluminescence of InAs surface quantum dots: intensity enhancement and strain control by underlying quantum dots

2022

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“…Investigations have focused on optical transitions around the quantum dots [29] and the wetting layer, while few works have been done considering the effect of photoexcited free carriers in buffer layer traveling to the surface, i. e., towards QDs [28,30].…”

Section: Introductionmentioning

confidence: 99%

Photoreflectance study of the GaAs buffer layer in InAs/GaAs quantum dots

Trujillo

Barragán

Calderón

et al. 2017

Superficies y Vacio

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GaAs buffer layer in InAs/GaAs quantum dots (QDs) was investigated by Photoreflectance (PR) technique at 300 K. PR spectra obtained were compared with commercial GaAs sample PR spectra, and they were analyzed by using the derivative Lorentzian functions as proposed by Aspnes in the middle field regimen. PR spectra in InAs/GaAs QDs sample was attributed to the photoreflectance response in the GaAs buffer layer. Band bending energies were calculated for laser intensities from 1 mW to 21 mW. The photoreflectance comparative study in the samples was realized considering the difference in the parameters: electric field on the surface, broadening parameter, energy gained by photoexcited carriers due to the electric field applied, frequency of light and heavy holes and band bending energy values. The results suggest that the presence of InAs quantum dots increases the light and heavy holes frequencies and the band bending energy values; and decreases the electric field on the surface, the broadening parameter and the energy gained by photoexcited carriers. We found that InAs QDs presence modifies the surface electrical field around one order of magnitude in the GaAs buffer layer and this behavior can be attributed to surface passivation.

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