Fabrication of GaSb quantum rings on GaAs(0 0 1) by droplet epitaxy

Kunrugsa, Maetee; Tung, Kar Hoo Patrick; Danner, Aaron J.; Panyakeow, Somsak; Ratanathammaphan, Somchai

doi:10.1016/j.jcrysgro.2015.01.018

Cited by 8 publications

(8 citation statements)

References 17 publications

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“…where k is the Boltzmann constant, and T is the temperature. Although holes in the GaSb layer are rapidly captured by the GaSb NSs [7], the PL emission from the GaSb layer can be observed even at high temperatures in the case of GaSb/GaAs QRs grown by droplet epitaxy [26]. Nonetheless, PL spectra at high temperatures for the GaSb/GaAs QRDSs in literature were just focused on the QR and QD peaks [27].…”

Section: Rate Equation Modelmentioning

confidence: 99%

“…From the fabrication point of view, droplet epitaxy is a growth technique that offers a high degree of freedom to engineer the morphology of self-assembled NSs in comparison with the Stranski-Krastanov (SK) method [23]. Droplet epitaxy can fabricate various kinds of the GaSb/GaAs NSs by tailoring the growth conditions [24][25][26][27]. Understanding of the optical properties and carrier dynamics is essential for the development of NS-based optoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

“…Understanding of the optical properties and carrier dynamics is essential for the development of NS-based optoelectronic devices. The optical properties of the GaSb/GaAs NSs have been extensively investigated by temperature-and power-dependent photoluminescence (PL) [4,26,28,29], while their carrier dynamics have been studied by deep level transient spectroscopy [1], admittance spectroscopy [2], two-color excitation approach [3], and time-resolved photoluminescence (TRPL) [7,8]. For the TRPL measurement, the carrier dynamics in the GaSb/GaAs NSs are simply analyzed by fitting the TRPL results to exponential decay functions [7].…”

Section: Introductionmentioning

confidence: 99%

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Quantitative description of carrier dynamics in GaSb/GaAs quantum-ring-with-dot structures

Kunrugsa¹

2021

J. Phys. D: Appl. Phys.

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Self-assembled GaSb/GaAs quantum-ring-with-dot structures (QRDSs) are the nanostructures exhibiting type-II band alignment. Each QRDS consists of both quantum ring (QR) and quantum dot (QD) parts which have their own energy levels. In this work, the carrier dynamics in the GaSb/GaAs QRDSs are explored and quantitatively described by a rate equation model which is developed from experimental photoluminescence (PL) spectra in literature. The model is comprised of the carrier transition rates and activation energies involved the transfer processes of thermal-excited carriers. The difference between the QR and QD PL intensities is also taken into account in the model. Electronic structures of a single QRDS are calculated in order to determine the overlap between electron and hole wave functions that can be used for estimating the radiative transition rates. Numerical values of the radiative and non-radiative transition rates, carrier capture and escape rates, and activation energies are presented. The PL spectra obtained from the model are consistent with the reported experimental data.

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Section: Rate Equation Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantitative description of carrier dynamics in GaSb/GaAs quantum-ring-with-dot structures

Kunrugsa¹

2021

J. Phys. D: Appl. Phys.

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“…For the undoped GaSb sample, these peaks are found at: P1 (0.959 eV), P2 (1.142 eV), P3 (1.319 eV) and P4 (1.485 eV), respectively. This PL peak energy range was reported only in GaSb-based nanostructures grown on GaAs substrate, such as quantum rings and quantum dots [16,17], and it is higher than the PL energy in most of the GaSb epilayers grown on GaAs reported previously (0.71-0.83 eV), [8,9,[18][19][20][21][22][23][24] regardless of the growth techniques and doping condition. We notice that the thickness of GaSb layers investigated in those reports range from 1 -20 µm, which is significantly larger than that of the samples studied in the current work, i.e.…”

Section: Resultsmentioning

confidence: 56%

Optical properties of beryllium-doped GaSb epilayers grown on GaAs substrate

Chen

Shao

et al. 2018

Infrared Physics & Technology

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In this work, the effects of p-type beryllium (Be) doping on the optical properties of GaSb epilayers grown on GaAs substrate by Molecular Beam Epitaxy (MBE) have been studied. Temperature-and excitation power-dependent photoluminescence (PL) measurements were performed on both nominally undoped and intentionally Be-doped GaSb layers. Clear PL emissions are observable even at the temperature of 270 K from both layers, indicating the high material quality. In the Be-doped GaSb layer, the transition energies of main PL features exhibit red-shift up to ~7 meV, and the peak widths characterized by Full-Widthat-Half-Maximum (FWHM) also decrease. In addition, analysis on the PL integrated intensity in the Be-doped sample reveals a gain of emission signal, as well as a larger carrier thermal activation energy. These distinctive PL behaviors identified in the Be-doped GaSb layer suggest that the residual compressive strain is effectively relaxed in the epilayer, due possibly to the reduction of dislocation density in the GaSb layer with the intentional incorporation of Be dopants. Our results confirm the role of Be as a promising dopant in the improvement of crystalline quality in GaSb, which is a crucial factor for growth and fabrication of high quality strain-free GaSb-based devices on foreign substrates.

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“…For the same deposition amount, with the increase of deposition rate, the relaxation time of aluminum droplets decreases and the density of holes increases. The shorter relaxation time means that the diffusion length of aluminum atoms decreases (Kunrugsa et al 2015), so it is unable to converge into larger aluminum droplets, and the size of the hole decreases gradually. It is consistent with the characterization and verification of the sample in Fig.…”

Section: Surface Morphology Of Nanoporous Before and After Annealingmentioning

confidence: 99%

Study on the asymmetry of nanopore in Al droplet etching

Shen

Liu

et al. 2021

Opt Quant Electron

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In the local droplet etching (LDE) method, the fine split structure (FSS) of quantum dots (QDs) is directly related to the shape of the nanopores formed after annealing. The formation of highly symmetrical nanoporous is the key to the preparation of GaAs/AlGaAs QDs with small FSS. The measurement and characterization of the nano pore shape before and after annealing showed that the density of the nano pore contours is different in different directions, indicating that the slope of the sidewall of the nano pore is different. Therefore, the QDs formed by LDE still have FSS. It has also been observed in experiments that one of the reasons for the asymmetry of the nanoporous is that the etching points covered by the Al droplets on the AlGaAs surface are not in the center of the droplets, which is caused by the supersaturation and maturation of Al atoms during the formation of the droplets. The asymmetry of the annular wall of the nano pore will cause the increase of the FSS of the QDs in the shallow nano pore. When the nano pore is deep enough, the influence of the annular wall of the nano pore on the QDs can be completely ignored, which greatly simplifies the preparation of nano pore. It has certain guiding significance of the preparation of nanoporous required for the growth of QDs with small FSS.

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Fabrication of GaSb quantum rings on GaAs(0 0 1) by droplet epitaxy

Cited by 8 publications

References 17 publications

Quantitative description of carrier dynamics in GaSb/GaAs quantum-ring-with-dot structures

Quantitative description of carrier dynamics in GaSb/GaAs quantum-ring-with-dot structures

Optical properties of beryllium-doped GaSb epilayers grown on GaAs substrate

Study on the asymmetry of nanopore in Al droplet etching

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