Hole capture and emission dynamics of type-II GaSb/GaAs quantum ring solar cells

Wagener, M.; Montesdeoca, Denise; Lu, Qi; Marshall, Andrew; Krier, A.; Botha, J.R.; Carrington, Peter J.

doi:10.1016/j.solmat.2018.07.030

Cited by 8 publications

(5 citation statements)

References 27 publications

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“…Self-assembled GaSb/GaAs nanostructures (NSs) such as quantum dots (QDs) and quantum rings (QRs) exhibit the strong localization of holes [1][2][3] because of their type-II band alignment which holes are only confined in the GaSb NSs, whereas electrons dwell in the GaAs region around the NSs [4][5][6]. This situation reduces the overlap between electron and hole wave functions [5,6], and results in long carrier lifetimes [7,8].…”

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: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Kunrugsa¹

2021

J. Phys. D: Appl. Phys.

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“…In the past, automatic generation control was used in thermal system consisting of single area with simple design [2]. This is extended still for thermal system operating in multi-area which is realistic with physical constraint consideration namely generation rate constraints and governor dead band with their non-linearity in a system of multi area [3]. Automatic generation control applied for system with multi area which includes thermal power unit, hydro power unit and gas power unit is presented [4].…”

Section: Introductionmentioning

confidence: 99%

Design of automation control thermal system integrated with parabolic trough collector based solar plant

Nattappan¹,

Ganesan²,

Thiagarajan³

et al. 2022

THERM SCI

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This paper presents enhanced design for Automation control of processes involved in a solar system which utilizes programmable logic controller to automate tracking system for obtaining maximum solar radiation. Three areas are involved in this proposed multi area system where first and second area considers solar power plant with thermal system based parabolic trough collector with fixed solar isolation and random isolation of solar energy whereas third area comprises of solar thermal system with dish Stirling realistic unit. Energy efficiency can be increased by using solar concentrator along with Stirling engine. Optimization of gain of the controller is by utilizing crow search novel algorithm. Crow search algorithm is an optimization technique, which provides better performance at complex time varying noisy condition and time in-varying noisy condition. The Proposed controller is evaluated by obtaining the optimized parameters of the system whose comparison is done by operating proposed controller with & without renewable sources of energy thereby revealing better performance for both conditions. Testing is done in different areas with fixed solar isolation and random stisolation of solar energy involved in solar thermal power plant based on parabolic trough collector. Gain and parameters of the controller of the solar power plant are optimized by utilizing automation for operation of solar concentrator with parabolic Trough collector. Data acquisition and monitoring is done by human machine interface (HMI) in order to report safe operation. The Simulation results of integrated solar thermal system involving dish Stirling with parabolic trough collector, shows that dynamic response of the proposed controller operating with renewable solar energy is better than that of non-renewable energy source.

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“…In particular, QDs have atom-like features resulting in a discrete density of states. Consequently, several works studied the fundamental properties [1][2][3] and the practical applications [4][5][6][7][8][9][10][11][12][13] of QDs. A special type of 0D nanostructures has been achieved since the late 90s -the quantum ring (QR) [1,14,15].…”

Section: Introductionmentioning

confidence: 99%

“…A special type of 0D nanostructures has been achieved since the late 90s -the quantum ring (QR) [1,14,15]. This nanostructure showed improved performance in many applications as solar cells [4][5][6][7] and emission devices [11][12][13]. Specifically, GaSb/GaAs nanostructures gained more interest in the last decade, mainly due to their type II nature.…”

Section: Introductionmentioning

confidence: 99%

Effects of Confining the Electron in a Double Quantum Well on the Excitonic Properties of the GaSb Quantum Ring

Kehili¹,

Sellami²,

Mansour³

et al. 2020

J. Nano- Electron. Phys.

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We studied theoretically the evolution of excitonic properties of GaSb quantum ring located inside the AlAs/GaAs/InGaAs/AlAs double quantum well with the wells (GaAs and InGaAs) thicknesses. The quantum ring is placed between the wells. In this type II nanostructure, the hole is confined inside the quantum ring and the electron is confined in the GaAs and InGaAs layers. The hole and the electron states were computed using the effective mass and the Hartree approximations. Then, the exciton energy, binding energy and lifetime were calculated. We found that varying the thickness of the well, we can control the localization of the electron wavefunction. Indeed, it can be above or below the quantum ring depending on the thicknesses of the GaAs and InGaAs layers. This has an important influence on the overlapping of the electron wavefunction with that of the hole which rests confined inside the quantum ring. Consequently, we can manipulate the excitonic properties, like energy, binding energy and lifetime via the electron and hole wavefunctions overlap. Thus, the studied systems can be used in tunable nano-optoelectronic devices. Furthermore, the use of the InGaAs layer as a capping layer of the quantum ring, instead of the GaAs layer as in an ordinary quantum ring, allows preserving the original properties of this nanostructure before the deposition of the capping layer.

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Hole capture and emission dynamics of type-II GaSb/GaAs quantum ring solar cells

Cited by 8 publications

References 27 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

Design of automation control thermal system integrated with parabolic trough collector based solar plant

Effects of Confining the Electron in a Double Quantum Well on the Excitonic Properties of the GaSb Quantum Ring

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