Title :
Metamorphic GaInP/GaInAs/Ge triple-junction solar cells with ≫ 41 % efficiency
Author :
Dimroth, Frank ; Guter, W. ; Schone, J. ; Welser, E. ; Steiner, M. ; Oliva, E. ; Wekkeli, A. ; Siefer, G. ; Philipps, SP ; Bett, A.W.
Author_Institution :
Fraunhofer Inst. for Solar Energy Syst., Freiburg, Germany
Abstract :
The use of lattice-mismatched materials offers an additional degree of freedom to the design of an optimum bandgap combination in a multi-junction solar cell. This allows for achieving higher conversion efficiencies compared to state-of-the-art lattice-matched systems if the material quality of the pn-junctions can be kept sufficiently high. Work performed at the Fraunhofer ISE on metamorphic GaInP/GaInAs/Ge triple-junction solar cells with 1.2% lattice-mismatch between the middle and bottom cell recently yielded a new record efficiency of 41.1% under 454-fold concentration of the AM1.5d spectrum. This paper summarizes the main benefits of the metamorphic solar cell approach and discusses some of the challenges associated with the development of this device structure.
Keywords :
III-V semiconductors; elemental semiconductors; gallium compounds; germanium; indium compounds; p-n junctions; solar cells; Fraunhofer ISE; GaInP-GaInAs-Ge; conversion efficiency; lattice-mismatched materials; metamorphic triple-junction solar cells; optimum bandgap combination; pn-junctions; Conductive films; Conductivity; Electrodes; Epitaxial growth; Glass; Molecular beam epitaxial growth; Photovoltaic cells; Substrates; Transistors; X-ray scattering;
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2009 34th IEEE
Conference_Location :
Philadelphia, PA
Print_ISBN :
978-1-4244-2949-3
Electronic_ISBN :
0160-8371
DOI :
10.1109/PVSC.2009.5411199
