Si-Based Tandem Solar Cells

© Fraunhofer ISE

We have been carrying out research into crystalline Si-based tandem solar cells at Fraunhofer ISE for several years. During this period we have developed extensive know-how in fields including the application of silicon carbide (SiC) which we use as a matrix material for Si nano crystals. Apart from the production of these Si nano materials using plasma-enhanced chemical vapor deposition (PECVD) and solid phase crystallization (SPC), our work is focused on crystallographic characterization and the development of simple structures as well as the measuring apparatus required for this research. Further key areas of research being carried out by our team are the determination of transport and recombination properties using electro-optic measurement methods such as time-resolved photoluminescence as well as specially developed measurement structures.

We are cooperating with prestigious research groups and companies at a national and international level to achieve our stated goal of producing tandem solar cells from these new absorber materials.

Key areas of research:

  • Deposition of multi-layers using PECVD
  • Solid phase crystallization (SPC) in different types of furnace
  • Material characterization (XRD, Raman, FTIR, AFM)
  • Simple structures for measuring optoelectronic properties
  • Time-resolved photoluminescence
  • Sigma (T) measurement stand with different illumination sources
  • Si-QP based solar cell structures
  • Tunnel diodes
  • Simulations of solar cell structures


Laboratories and equipment:

  • Inline zone melting system (ZMR400con)
  • Zone melting system (ZMR100)
  • Various optically or resistance-heated tempering plants
  • Industrial PECVD inline coating systems for coating with silicon carbide
  • Laboratory units AK 400 (Roth&Rau) for PECVD coating
  • Clean room


In principle sample sizes up to 400x400 mm 2 can be processed.