Minority carrier lifetime of GaAs on silicon

Ahrenkiel, R. K.; Al‐Jassim, Mowafak; Dunlavy, D. J.; Jones, K. M.; Vernon, S. M.; Tobin, S. P.; Haven, V. E.

doi:10.1109/pvsc.1988.105790

Cited by 9 publications

(11 citation statements)

References 10 publications

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“…Defects and dislocations which are generated at the III-V/Si hetero-interface may serve as recombination centers and impede the minority carrier lifetime and hence their diffusion length. This degradation in lifetime may significantly impede the cell performance [4]- [6]. The effective minority carrier lifetime (τ n or τ p ) in a latticemismatched system varies as a function of TDD (f (τ TDD )) [7], [16] and can be expressed as, where τ°p and τ°n are the minority carrier lifetime for a dislocation free material.…”

Section: Simulation Modelmentioning

confidence: 99%

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Design of metamorphic dual-junction InGaP/GaAs solar cell on Si with efficiency greater than 29% using finite element analysis

Jain

Hudait

2012

2012 38th IEEE Photovoltaic Specialists Conference

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Heterogeneous integration of multijunction III-V solar cells on Si is a promising solution for the widespread commercialization of III-V cells. However, the polar on non-polar epitaxy and 4% lattice-mismatch between GaAs and Si results in formation of defects and dislocations, which can significantly impede the minority carrier lifetime and hence the cell performance. We have investigated the impact of threading dislocation density on the performance of dual-junction (2J) n+/p InGaP/GaAs solar cells on Si. Using our calibrated model, the metamorphic 2J cell on Si was optimized by tailoring the 2J cell design on Si to achieve current-matching between the subcells at a realistic threading dislocation density of 10 6 cm -2 . We present a novel 2J InGaP/GaAs cell design on Si at a threading dislocation density of 10 6 cm -2 which exhibited a theoretical conversion efficiency of greater than 29% at AM1.5G spectrum, indicating a path for viable III-V multijunction cell technology on Si.Index Terms -III-V semiconductor materials, charge carrier lifetime, epitaxial layers, photovoltaic cells, semiconductor device modeling, short circuit currents, silicon.

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Section: Simulation Modelmentioning

confidence: 99%

“…The impact of TDD on cell performance has been previously investigated [4]- [9], however, their analysis was limited to 1J GaAs cell on Si. J sc used for modeling the impact of TDD on V oc was assumed to be independent of TDD [8].…”

Section: Introductionmentioning

confidence: 99%

Design of metamorphic dual-junction InGaP/GaAs solar cell on Si with efficiency greater than 29% using finite element analysis

Jain

Hudait

2012

2012 38th IEEE Photovoltaic Specialists Conference

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“…A higher TDD significantly affects the minority carrier lifetime and reduces the open-circuit voltage (V oc ) of the device [4]. By lattice matching the top and bottom cells, the voltage loss due to threading dislocations can be minimized.…”

Section: Introductionmentioning

confidence: 99%

Dual-junction GaAsP/SiGe on silicon tandem solar cells

Diaz

Wang

Gerger

et al. 2014

2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)

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GaAsP/SiGe dual-junction solar cells have been grown on silicon substrates which have the potential of achieving tandem efficiencies of 40%. This lattice-matched structure facilitates high performance from the III-V top cell while maintaining the cost advantages of silicon solar cells. The SiGe graded buffer allows for lattice matching of the top and bottom cell while providing a low dislocation interface between the silicon substrate and the device layers. Initial structures have reached an efficiency of 18.9%. Near term improvements to 25.0% under AM1.5G will be described.Index Terms -tandem solar cells, gallium arsenide phosphide, semiconductor materials, silicon germanium.

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“…Metamorphic solar cells have demonstrated efficiencies which are higher than conventional latticed matched multi junction solar cells. But the major drawback in using metamorphic devices is the presence of crystalline defects which are in the range of 5x10 6 to 10 8 cm -2 [2,3] arising due to lattice mismatch between sub cells. These defects cause reduction in minority carrier lifetime and result in efficiency degradation, hence thick buffer layer are used in order reduce these defects.…”

Section: -Introductionmentioning

confidence: 99%

Modeling of defect-tolerant thin multi-junction solar cells for space application

2012

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Using drift-diffusion model and considering experimental III-V material parameters, AM0 efficiencies of multijunction solar cells have been calculated and the effects of dislocations and radiation damage have been analyzed. It is shown that ultrathin multi-junction devices perform better in presence of dislocations or/and radiation harsh environment compared to conventional thick counterpart. Under high radiation doses the optimization of the device design for Ga 0.51 In 0.49 P/GaAs multijunction devices leads to a significant improvement of end of life (EOL) efficiencies (i.e. under a dose of 10 16 cm -2 1MeV electron fluence the device efficiency can be improved 2.5 fold by fine tuning the design . In addition these calculations indicate that for radiation doses in excess of an equivalent 1x10 15 cm -2 1 MeV electron fluence (~10 years in Geostationary orbit) the optimized design makes these design somewhat insensitive to the presence of large of other minority carrier traps such as those introduced by crystalline defects (i.e. dislocations). The results suggest that by optimizing the device design, one can obtain nearly the same EOL efficiencies for highly dislocated metamorphic/heteroepitaxial solar cells than those of an ideal defect free device. These findings could be of importance to the manufacture of current metamorphic space cells as to some extent they indicate possibilities for circumventing the need for sophisticated defect filtering techniques. 1-INTRODUCTIONSince the launch of Vanguard, the first man-made solar powered satellite, the quest for solar cells with higher efficiencies and improved radiation tolerance has been of paramount importance to space power system designers. Within this context solar cells based on III-V materials, mere laboratory curiosities of early nineties, have established themselves as the prime candidates for space orbital operations. . III-V lattice-matched multijunction devices based on GaInP-GaAs-Ge have shown efficiencies of in excess of 30% AM0 [1]. In order to achieve higher efficiencies in multijunction solar cells, flexibility in choice of band gaps is required which is not constraint by lattice matching condition. This flexibility in choice of band gap is used in metamorphic solar cells. Metamorphic solar cells have demonstrated efficiencies which are higher than conventional latticed matched multi junction solar cells. But the major drawback in using metamorphic devices is the presence of crystalline defects which are in the range of 5x10 6 to 10 8 cm -2 [2,3] arising due to lattice mismatch between sub cells. These defects cause reduction in minority carrier lifetime and result in efficiency degradation, hence thick buffer layer are used in order reduce these defects. Space radiation also causes reduction in diffusion length and lifetimes. Hence solar cells in space slowly degrade due to presence of this radiation. It is been shown that optimization of single junction GaAs solar cell would give better end of life performance (EOL) than conventional solar cells ...

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Minority carrier lifetime of GaAs on silicon

Cited by 9 publications

References 10 publications

Design of metamorphic dual-junction InGaP/GaAs solar cell on Si with efficiency greater than 29% using finite element analysis

Design of metamorphic dual-junction InGaP/GaAs solar cell on Si with efficiency greater than 29% using finite element analysis

Dual-junction GaAsP/SiGe on silicon tandem solar cells

Modeling of defect-tolerant thin multi-junction solar cells for space application

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