Thick-well quantum-structured solar cells: design criteria for nano-enhanced absorbers

Welser, Roger E.

doi:10.1117/12.2001298

Cited by 4 publications

(3 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Clear enhancements in the infrared spectral response have been experimentally observed in both quantum well and quantum dot solar cells. Recently, GaAsbased quantum well solar cells with a novel material structure which minimizes non-radiative recombination have also achieved record-high open circuit voltages, in some cases exceeding 1 V at one-sun bias levels [19,30]. In this section, we detail the additional performance benefits resulting from the use of compositionally step-graded InGaAs well designs.…”

Section: High-voltage Nano-enhanced Devices With Suppressed Radiativementioning

confidence: 99%

The Physics of High-Efficiency Thin-Film III-V Solar Cells

Welser¹,

Sood²,

Laghumavarapu³

et al. 2015

Solar Cells - New Approaches and Reviews

Self Cite

View full text Add to dashboard Cite

Section: High-voltage Nano-enhanced Devices With Suppressed Radiativementioning

confidence: 99%

The Physics of High-Efficiency Thin-Film III-V Solar Cells

Welser¹,

Sood²,

Laghumavarapu³

et al. 2015

Solar Cells - New Approaches and Reviews

Self Cite

View full text Add to dashboard Cite

“…To overcome this transport problem, various strategies based on MQW structural design have been proposed. These include using a superlattice with ultra‐thin barriers to facilitate tunneling , limiting the number of thick wells to suppress non‐radiative recombination , using step‐designed MQWs for efficient thermionic carrier escape , and performing quick carrier extraction from deep wells via resonant‐tunneling‐assisted processes .…”

Section: Introductionmentioning

confidence: 99%

100-period, 1.23-eV bandgap InGaAs/GaAsP quantum wells for high-efficiency GaAs solar cells: toward current-matched Ge-based tandem cells

Fujii

Toprasertpong

Wang

et al. 2013

Prog. Photovolt: Res. Appl.

View full text Add to dashboard Cite

Major challenges for InGaAs/GaAsP multiple quantum well (MQW) solar cells include both the difficulty in designing suitable structures and, because of the strain-balancing requirement, growing high-quality crystals. The present paper proposes a comprehensive design principle for MQWs that overcomes the trade-off between light absorption and carrier transport that is based, in particular, on a systematical investigation of GaAsP barrier effects on carrier dynamics that occur for various barrier widths and heights. The fundamental strategies related to structure optimization are as follows: (i) acknowledging that InGaAs wells should be thinner and deeper for a given bandgap to achieve both a higher absorption coefficient for 1e-1hh transitions and a lower compressive strain accumulation; (ii) understanding that GaAs interlayers with thicknesses of just a few nanometers effectively extend the absorption edge without additional compressive strain and suppress lattice relaxation during growth; and (iii) understanding that GaAsP barriers should be thinner than 3 nm to facilitate tunneling transport and that their phosphorus content should be minimized while avoiding detrimental lattice relaxation. After structural optimization of 1.23-eV bandgap quantum wells, a cell with 100-period In 0.30 GaAs(3.5 nm)/GaAs(2.7 nm)/GaAsP 0.40 (3.0 nm) MQWs exhibited significantly improved performance, showing 16.2% AM 1.5 efficiency without an anti-reflection coating, and a 70% internal quantum efficiency beyond the GaAs band edge. When compared with the GaAs control cell, the optimized cell showed an absolute enhancement in AM 1.5 efficiency, and 1.22 times higher efficiency with 38% current enhancement with an AM 1.5 cut-off using a 665-nm long-pass filter, thus indicating the strong potential of MQW cells in Ge-based 3-J tandem devices.

show abstract

“…Radiative processes have an n = 1 voltage dependence, both in the quasi-neutral region of the baseline cell and in the quantum well region [15]. Radiative emissions from the quantum well region have been previously shown to dominate the dark diode characteristics of quantum well solar cells at high bias levels, even when nonradiative processes limit 1-sun photovoltaic device performance [16], [17].…”

Section: Analytical Device Modelmentioning

confidence: 99%

Impact of Well Number on High-Efficiency Strain-Balanced Quantum-Well Solar Cells

Welser

Polly

Bogner

et al. 2023

IEEE J. Photovoltaics

Self Cite

View full text Add to dashboard Cite

The addition of lower energy-gap InGaAs quantum wells to the depletion region of GaAs solar cells is an established approach to enhance photovoltaic performance by extending infrared collection. However, maintaining a high open-circuit voltage (V oc ) when including quantum wells has proven more challenging. In this article, we report on high-efficiency (η > 23.5% AM0) strainbalanced quantum well (SBQW) solar cells with increased current output and efficiency while maintaining the same high open-circuit voltage of baseline devices without quantum wells (V oc > 1.02 V). The single-junction GaAs-based device structures discussed herein employ a radiation-tolerant, n-i-p front-junction architecture and include both an InGaP heterojunction (HJ) emitter and in most cases an underlying AlGaAs distributed Bragg reflector.The impact of well number on photovoltaic device characteristics is described using an analytical model that assumes current collection, radiative recombination, and nonradiative recombination all increase with well number and are additive to the baseline cell. The highest V oc and efficiency SBQW devices employ shallow 9.2 nm In 0.07 Ga 0.93 As quantum wells and 11.5 nm GaAs 0.90 P 0.10 barrier layers to maintain strain balancing. Increasing the indium composition in the wells from 7% to 10% to form deeper wells requires a thicker strain-balancing barrier layer and results in an apparent increase in radiative recombination and decreased V oc . Single-junction high-efficiency SBQW device performance is also demonstrated in thinner base-layer structures with graded HJs-device structures suitable for inclusion in radiation-tolerant multi-junction structures.

show abstract

Thick-well quantum-structured solar cells: design criteria for nano-enhanced absorbers

Cited by 4 publications

References 7 publications

The Physics of High-Efficiency Thin-Film III-V Solar Cells

The Physics of High-Efficiency Thin-Film III-V Solar Cells

100-period, 1.23-eV bandgap InGaAs/GaAsP quantum wells for high-efficiency GaAs solar cells: toward current-matched Ge-based tandem cells

Impact of Well Number on High-Efficiency Strain-Balanced Quantum-Well Solar Cells

Contact Info

Product

Resources

About