AIXTRON SE Decisive progress in multi-junction solar cells / Record efficiency of highly efficient III-V multi-junction solar cells on silicon / High energy efficiency at attractive cost
Decisive progress in multi-junction solar cells
Record efficiency of highly efficient III-V multi-junction solar cells on silicon / High energy efficiency at attractive cost
Herzogenrath, Germany, September 15, 2020 - A central stage in the development of economic solutions for the industrial use of multi-junction solar cells for power generation has been reached. For the first time, an efficiency of 25.9 percent has been achieved with a multi-junction solar cell grown directly on a silicon substrate.
This record figure was achieved by researchers at the Fraunhofer Institute for Solar Energy Systems ISE in close cooperation with the Technical University of Ilmenau, the Philipps University of Marburg and the epitaxy experts at AIXTRON SE, a leading provider of deposition equipment for the semiconductor industry, as part of the funded "MehrSi" project. The team, together with scientists from the Fraunhofer ISE, succeeded in optimizing the layer structure and technology.
Key technology tandem photovoltaics
"For the first time we have now been able to realize a tandem solar cell based on a silicon wafer with such high efficiency," comments Dietmar Schmitz, Vice President Corporate Technology Transfer at AIXTRON SE. Until now, the production of III-V multi-junction solar cells has been based on a more expensive substrate material, for example also a compound semiconductor material.
Dietmar Schmitz emphasizes what is special about this basic research: "The gallium and phosphorus atoms must occupy the correct lattice positions at the interface with silicon. To achieve this, we have to control the atomic structure very well. This requires exceptionally high precision. In addition, to achieve the necessary high quality of the epi-wafers, it is crucial that a high crystal quality of all layers is achieved during epitaxial growth. This was achieved in the project thanks to the improved system technology developed by AIXTRON and the good cooperation with the project partners".