Renewable energy - Silicon solar cells

Photovoltaic Stacks

Apart from 'terrestrial' solar cells, IMEC also develops highly efficient solar cells for space applications. This type of solar cell is fabricated of III-V materials such as GaAs, InGaP and InGaNAs on top of a Ge substrate.

In 2002, IMEC again developed a solar cell that is amongst the best in the world. While a highly-efficient (24.5%) GaAs cell was developed the previous year, the focus in 2002 was on the Ge substrate. This was no longer used as a passive substrate but instead as a stand-alone germanium solar cell with a world-class AM1.5 energy conversion efficiency of 6.7%.

The stand-alone germanium solar cell can be used in several applications. A first application is found in the field of highly-efficient solar cells for power generation in satellites. In order to realize the required efficiency, multiple junctions are stacked on top of each other, either monolithically or mechanically. The germanium stand-alone cell serves as a bottom cell that can be mechanically stacked underneath a top cell consisting of III-V materials, such as GaAs and InGaP. In addition, this stand-alone germanium cell is very well suited for application in thermo photovoltaic (TPV) systems, where specific radiation produced by a heat source is converted into electricity. Finally this process may also be used to realize Ge photodetectors with a high sensitivity over a spectral band ranging from 400 till 1700nm.

Germanium solar cell with a world-class efficiency of 6.7%.

Further information and contact persons
Jef Poortmans
IMEC, Kapeldreef 75, B-3001 Leuven, Belgium
Tel. +32 16 281.302, fax. +32 16 281 501

Giovanni Flamand
IMEC, Kapeldreef 75, B-3001 Leuven, Belgium
Tel. +32 16 281.866, fax. +32 16 281 501

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Last modified on: Tuesday, 23-Dec-2003 15:30:52 CET