Open circuit voltage increase of GaSb/GaAs quantum ring solar cells under high hydrostatic pressure

Montesdeoca, Denise; Carrington, Peter J.; Marko, Igor P.; Wagener, M.; Sweeney, Stephen J.; Krier, A.

doi:10.1016/j.solmat.2018.07.028

Cited by 5 publications

(3 citation statements)

References 30 publications

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“…Experimental analysis of prototype IBSCs based on type-II GaAs 1−x Sb x /GaAs vertical QR stacks has revealed several promising properties compared to conventional QD-IBSCs, including (i) enhanced TSPA and external quantum efficiency, 21,22 (ii) reduced losses via radiative recombination, leading to improved carrier extraction and overall efficiency, 23 and (iii) recovery of V OC under concentrated illumination. [24][25][26] Despite numerous and ongoing experimental investigations of type-II GaAs 1−x Sb x /GaAs QRs for IBSC applications, there is little detailed information available in the literature regarding their electronic properties from a theoretical perspective. Here, we present a combined analytical and numerical analysis of the electronic properties of GaAs 1−x Sb x /GaAs QRs and demonstrate that minor changes in morphology, compatible with established epitaxial growth, can be exploited to tune the QR hole ground state (IB) to an optimum energy to maximise IBSC efficiency.…”

Section: Introductionmentioning

confidence: 99%

Electronic properties of type-II $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$/GaAs quantum rings for applications in intermediate band solar cells

2020

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We present a theoretical analysis of the electronic properties of type-II GaAs1−xSbx/GaAs quantum rings (QRs), from the perspective of applications in intermediate band solar cells (IBSCs). We outline the analytical solution of Schrödinger's equation for a cylindrical QR of infinite potential depth, and describe the evolution of the QR ground state with QR morphology. Having used this analytical model to elucidate general aspects of the electronic properties of QRs, we undertake multiband k•p calculations -including strain and piezoelectric effects -for realistic GaAs1−xSbx/GaAs QRs. Our k•p calculations confirm that the large type-II band offsets in GaAs1−xSbx/GaAs QRs provide strong confinement of holes, and further indicate the presence of resonant (quasi-bound) electron states which localise in the centre of the QR. From the perspective of IBSC design the calculated electronic properties demonstrate several benefits, including (i) large hole ionisation energies, mitigating thermionic emission from the intermediate band, and (ii) electron-hole spatial overlaps exceeding those in conventional GaAs1−xSbx/GaAs QDs, with the potential to engineer these overlaps via the QR morphology so as to manage the trade-off between optical absorption and radiative recombination. Overall, our analysis highlights the flexibility offered by the QR geometry from the perspective of band structure engineering, and identifies specific combinations of QR alloy composition and morphology which offer optimised sub-band gap energies for QR-based IBSCs.

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Section: Introductionmentioning

confidence: 99%

Electronic properties of type-II $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$/GaAs quantum rings for applications in intermediate band solar cells

2020

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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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Effect of Thermal Annealing on Absorption and Hole Escape Processes in Type II GaSb/GaAs Quantum Dots: Implications for Solar Cell Design

Boustanji

Jaziri

Tomić

2019

IEEE J. Photovoltaics

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Open circuit voltage increase of GaSb/GaAs quantum ring solar cells under high hydrostatic pressure

Cited by 5 publications

References 30 publications

Electronic properties of type-II $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$/GaAs quantum rings for applications in intermediate band solar cells

Electronic properties of type-II $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$/GaAs quantum rings for applications in intermediate band solar cells

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

Effect of Thermal Annealing on Absorption and Hole Escape Processes in Type II GaSb/GaAs Quantum Dots: Implications for Solar Cell Design

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