Dual junction GaInP/GaAs solar cells grown on metamorphic SiGe/Si substrates with high open circuit voltage

Lueck, Matthew; Andre, C.; Pitera, Arthur J.; Lee, Minjoo Larry; Fitzgerald, Eugene A.; Ringel, S. A.

doi:10.1109/led.2006.870250

Cited by 133 publications

(85 citation statements)

References 15 publications

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“…The modelling parameters and operating conditions were chosen to be similar to those presented in other studies. [35][36][37][38] In order to validate the mass transport effects in the EC, a comparison was made with fuel cell (FC) data available from Kim et al 38 assuming the electrolysis to be a perfectly reversible process of FC. The voltage scale was then adapted using V new = (E eq −V exp ) + E eq , where V exp is the experimentally measured voltage, V new is the adapted voltage, and E eq is the equilibrium voltage of 1.208 at 353 K, eq.…”

Section: Resultsmentioning

confidence: 99%

Integrated Photo-Electrochemical Solar Fuel Generators under Concentrated Irradiation

Tembhurne

Haussener

2016

J. Electrochem. Soc.

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We investigate the direct conversion of solar energy and water into a storable fuel via integrated photo-electrochemical (IPEC) devices. Here we focus particularly on a device design which uses concentrated solar irradiation to reduce the use of rare and expensive components, such as light absorbers and catalysts. We present a 2-dimensional coupled multi-physics model using finite element and finite volume methods to predict the performance of the IPEC device. Our model accounts for charge generation and transport in the photoabsorber, charge transport in the membrane-separated catalysts, electrochemical reaction at the catalytic sites, fluid flow and species transport in the porous charge collectors and channels, and radiation absorption and heat transfer for all components. We then develop performance optimization strategies utilizing device design, component and material choice, and adaptation of operational conditions. Our model predicts that operation under high irradiation is possible and that dedicated thermal management can ensure high performant operation. The model shows to be a valuable tool for the design of IPEC devices under concentrated irradiation at elevated temperatures. To our knowledge, it is the most detailed yet computationally low-cost model of an IPEC device reported. The solar energy received on earth's surface can meet mankind's current and future energy demand.1,2 Direct conversion of solar energy and water into chemical energy via photo-electrochemical (PEC) processes is one viable route for renewable fuel processing and energy storage. Integrated photo-electrochemical (IPEC) devices, i.e. composed of an integrated buried photovoltaic (PV) component and an integrated electrochemical component (consisting of membraneseparated catalysts and porous charge collectors), allow circumvention of some of the challenges imposed by solid-liquid interfaces in traditional PEC devices, while also exhibiting potential to operate at higher efficiencies and lower cost than externally wired (non-integrated) PV plus electrolyzer (EC) devices. [3][4][5] We refer to the design as "integrated" to signify that the PV and electrolyzer components are area-matched and in direct contact, allowing heat transfer from one component to the other and for thermal management strategies to be applied. In order to increase the economic competitiveness of IPEC devices compared to conventional hydrogen generation pathways, we consider concentration of irradiation. [6][7][8] This leads to large driving current densities (approximately proportional to the concentration factor), and thus introduces larger overpotentials and potential mass transport limitations.9 Concentration also decreases the performance of the photoactive components due to increased temperature. On the other hand, the kinetics are enhanced with increased temperature. Ionic transport in the solid electrolyte is also enhanced with increased temperature, but this increase stops abruptly and sharply drops at temperatures above 120• C due to membrane dry out. ...

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Section: Resultsmentioning

confidence: 99%

Integrated Photo-Electrochemical Solar Fuel Generators under Concentrated Irradiation

Tembhurne

Haussener

2016

J. Electrochem. Soc.

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Section: Si X Ge 1-x Graded Buffersmentioning

confidence: 99%

“…Typically, the compositionally step-graded 12-µm thick SiGe buffers are grown by UHC-CVD on (100) Si with 6˚offcut toward <110> plane with final composition ending in 100% Ge Lueck et al 2006). A TDD of~2.1 Â 10 6 cm −2 was reported for fully relaxed Ge layers grown on SiGe/Si substrate Lueck et al 2006). For the III-V solar cell growth, an initial epitaxial Ge layer was grown by MBE followed by the growth of GaAs on Ge at an initial low growth temperature using migration-enhanced epitaxy, details of which can be found in Refs Sieg et al 1998).…”

Section: Si X Ge 1-x Graded Buffersmentioning

confidence: 99%

“…Such 1J GaAs solar cells on SiGe substrate were demonstrated to exhibit similar performance virtually independent of the cell area, thereby addressing the concern of thermal mismatch related issues between the GaAs epilayers and the Si substrate . Additionally, Lueck et al (2006) reported a 2J GaInP/GaAs solar cell on similar Ge/SiGe/Si substrate with an efficiency of 16.8% under AM1.5. The overall performance of the 2J cell was limited by poor antireflection coating, large grid coverage area, significant absorption in the GaAs tunnel junction and due to a lower V oc contribution from the top GaInP subcell (primarily due to a lower top cell bandgap) (Lueck et al 2006).…”

Section: Si X Ge 1-x Graded Buffersmentioning

confidence: 99%

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III–V Multijunction Solar Cell Integration with Silicon: Present Status, Challenges and Future Outlook

Jain

Hudait

2014

Energy Harvesting and Systems

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Achieving high-efficiency solar cells and at the same time driving down the cell cost has been among the key objectives for photovoltaic researchers to attain a lower levelized cost of energy (LCOE). While the performance of silicon (Si) based solar cells have almost saturated at an efficiency of~25%, III-V compound semiconductor based solar cells have steadily shown performance improvement at~1% (absolute) increase per year, with a recent record efficiency of 44.7%. Integration of such high-efficiency III-V multijunction solar cells on significantly cheaper and large area Si substrate has recently attracted immense interest to address the future LCOE roadmaps by unifying the high-efficiency merits of III-V materials with low-cost and abundance of Si. This review article will discuss the current progress in the development of III-V multijunction solar cell integration onto Si substrate. The current state-of-the-art for III-Von-Si solar cells along with their theoretical performance projections is presented. Next, the key design criteria and the technical challenges associated with the integration of III-V multijunction solar cells on Si are reviewed. Different technological routes for integrating III-V solar cells on Si substrate through heteroepitaxial integration and via mechanical stacking approach are presented. The key merits and technical challenges for all of the till-date available technologies are summarized. Finally, the prospects, opportunities and future outlook toward further advancing the performance of III-V-on-Si multijunction solar cells are discussed. With the plummeting price of Si solar cells accompanied with the tremendous headroom available for improving the III-V solar cell efficiencies, the future prospects for successful integration of III-V solar cell technology onto Si substrate look very promising to unlock an era of next generation of high-efficiency and low-cost photovoltaics.

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“…For these reasons different studies have been carried out to integrate Ge on Si with only a low density of defects in the active region [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Towards III-V solar cells on Si: Improvement in the crystalline quality of Ge-on-Si virtual substrates through low porosity porous silicon buffer layer and annealing

Calabrese¹,

Baricordi²,

Bernardoni³

et al. 2014

AIP Conference Proceedings

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Abstract.A comparison between the crystalline quality of Ge grown on bulk Si and on a low porosity porous Si (pSi) buffer layer using low energy plasma enhanced chemical vapor deposition is reported. Omega/2Theta coupled scans around the Ge and Si (004) diffraction peaks show a reduction of the Ge full-width at half maximum (FWHM) of 22.4% in presence of the pSi buffer layer, indicating it is effective in improving the epilayer crystalline quality. At the same time atomic force microscopy analysis shows an increase in root means square roughness for Ge grown on pSi from 38.5 nm to 48.0 nm, as a consequence of the larger surface roughness of pSi compared to bulk Si. The effect of 20 minutes vacuum annealing at 580°C is also investigated. The annealing leads to a FWHM reduction of 23% for Ge grown on Si and of 36.5% for Ge on pSi, resulting in a FWHM of 101 arcsec in the latter case. At the same time, the RMS roughness is reduced of 8.8% and of 46.5% for Ge grown on bulk Si and on pSi, respectively. The biggest improvement in the crystalline quality of Ge grown on pSi with respect to Ge grown on bulk Si observed after annealing is a consequence of the simultaneous reorganization of the Ge epilayer and the buffer layer driven by energy minimization. A low porosity buffer layer can thus be used for the growth of low defect density Ge on Si virtual substrates for the successive integration of III-V multijunction solar cells on Si. The suggested approach is simple and fast -thus allowing for high throughput-, moreover is cost effective and fully compatible with subsequent wafer processing. Finally it does not introduce new chemicals in the solar cell fabrication process and can be scaled to large area silicon wafers.

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Dual junction GaInP/GaAs solar cells grown on metamorphic SiGe/Si substrates with high open circuit voltage

Cited by 133 publications

References 15 publications

Integrated Photo-Electrochemical Solar Fuel Generators under Concentrated Irradiation

Integrated Photo-Electrochemical Solar Fuel Generators under Concentrated Irradiation

III–V Multijunction Solar Cell Integration with Silicon: Present Status, Challenges and Future Outlook

Towards III-V solar cells on Si: Improvement in the crystalline quality of Ge-on-Si virtual substrates through low porosity porous silicon buffer layer and annealing

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