Title :
LPE-GaAs and LBSF-Si solar cells for tandem concentrator application
Author :
Blieske, U. ; Sterk, S. ; Bett, A. ; Schumacher, J. ; Wettling, W. ; Martí, A. ; Terrón, M.J. ; Luque, A.
Author_Institution :
Fraunhofer-Inst. fur Solare Energiesysteme, Freiburg, Germany
Abstract :
Design and efficiency measurements of a mechanically stacked concentrator tandem solar cell are presented. The GaAs cell was grown by the LPE etch-back-regrowth method and has a diameter of 4 mm. The silicon solar cell is a high efficient LBSF concentrator solar cell of 5 mm diameter. Special care was taken to optimize the antireflection coatings on the back and front side of the GaAs solar cell. Both cells were processed at FhG-ISE in Freiburg. Their short circuit currents were measured at the ISE calibration laboratory under AM1.5d conditions. The efficiency measurements were performed at UPM-IES in Madrid under outdoor conditions. At 27 suns (AM1.5d, 25°C) the GaAs cell showed an efficiency of 22.9% and the silicon cell an efficiency of 2.9%. The two single cell efficiencies add to a tandem efficiency of 25.8% for the four terminal operation
Keywords :
III-V semiconductors; elemental semiconductors; gallium arsenide; liquid phase epitaxial growth; semiconductor device models; semiconductor device testing; semiconductor growth; silicon; solar cells; solar energy concentrators; 2.9 percent; 22.9 percent; 25 C; 25.8 percent; 4 mm; GaAs-Si; GaAs/Si tandem concentrator solar cells; LPE etch-back-regrowth method; antireflection coatings; calibration; design; efficiency measurements; mechanical stacking; short circuit current; Calibration; Coatings; Current measurement; Etching; Gallium arsenide; Laboratories; Mechanical variables measurement; Photovoltaic cells; Short circuit currents; Silicon;
Conference_Titel :
Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
0-7803-1460-3
DOI :
10.1109/WCPEC.1994.520739
