The epitaxial lift-off (ELO) technique can be used to separate a III-V solar cell structure from its underlying GaAs or Ge substrate. ELO from 4-inch Ge wafers is shown and 2-inch GaAs wafer reuse after lift-off is demonstrated without degradation in performance of the subsequent thin-film GaAs solar cells that were retrieved from it. Since a basic wet chemical smoothing etch procedure appeared insufficient to remove all the surface contamination, wafer re-preparation is done by a chemo-mechanical polishing procedure.
The project FULLSPECTRUM -an Integrated Project (IP) in the terminology of the European Commission -pursues a better exploitation of the FULL solar SPECTRUM by (1) further developing concepts already scientifically proven but not yet developed and (2) by trying to prove new ones in the search for a breakthrough in photovoltaic (PV) technology. More specific objectives are the development of: (a) III-V multijunction cells (MJC), (b) solar thermo-photovoltaic (TPV) converters, (c) intermediate band (IB) materials and cells (IBC), (d) molecular-based concepts (MBC) for full PV utilisation of the solar spectrum and (e) manufacturing technologies (MFG) for novel concepts including assembling. MJC technology towards 40% efficiency will be developed using lower cost substrates and high light concentration (up or above 1000 suns). TPV is a concept with a theoretically high efficiency limit because the entire energy of all the photons is used in the heating process and because the non-used photons can be fed back to the emitter, therefore helping in keeping it hot. In the IBC approach, sub-bandgap photons are exploited by means of an IB. Specific IB materials will be sought by direct synthesis suggested by material-band calculations and using nanotechnology in quantum dot (QD) IBCs. In the development of the MBC, topics such as the development of two-photon dye cells and the development of a static global (direct and diffuse) light concentrator by means of luminescent multicolour dyes and QDs, with the radiation confined by photonic crystals, will be particularly addressed. MFG include optoelectronic assembling techniques and coupling of light to cells with new-optic miniconcentrators. r
AZUR's latest lattice-matched triple junction space solar cell product has been designed for a high EOL efficiency by focusing the development on radiation hardness right from the beginning. These solar cells named as 3G30-Advanced show an efficiency of 29.5% at BOL and of 28.1% for EOL at 5E14 (1MeV) e-/cm 2 (AM0, 1367 W/m 2 , 28°C). Meanwhile more than 125,000 cells of this cell type have been delivered to customers worldwide. Cell thicknesses of 150 µm, 80µm or even as thin as 20µm are available. Besides the standard size of 8x4 cm 2 (with cropped corners) larger sizes such as 8x8cm 2 and 12x6 cm 2 are also available and provide equal performance. AZUR's next generation product will comprise a metamorphic 4-junction device targeting at 30% efficiency at EOL to be qualified in 2015/16. Furthermore, for arriving at more than 30% EOL efficiency with 4 -6 junction solar cells in a subsequent step, appropriate lattice-matched 1eV dilute nitride materials, inversely grown solar cells and semiconductor bonded cells are studied in cooperation with external partners. Index Terms -end-of-life-efficiency, GaAs based space solar cells, radiation damage, subcell design978-1-4799-4398-2/14/$31.00 ©2014 IEEE
We demonstrate how, using electroluminescence, the parameters characterizing the recombination center induced by irradiation in a solar cell can be measured. Because electroluminescence is able to provide information on an individual cell in a multijunction (MJ) cell device, independently of the others, we apply this technique to measure these parameters in InGaP/GaAs/Ge MJ cells. We then calculate the variations of the open-circuit voltage and short-circuit current of such cells versus fluence. The results are compared with experimental data obtained for 1 MeV electron irradiations.
This paper gives a review of the work performed in the framework of the EC-funded project FULLSPECTRUM aiming for higher photovoltaic (PV) conversion efficiencies by investigating GaInP∕GaInAs∕Ge triple-junction concentrator solar cells. Lattice mismatched structures reached efficiencies beyond 35% at 600 sun concentration level. These cells are now ready to enter the terrestrial PV market. The perspectives and challenges associated with the market introduction of these cells are addressed. Specifically issues of reliability and on-wafer characterization are discussed. A new characterization tool MAPCON was developed and is presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.