Description: The Helmholtz-Zentrum Berlin (HZB) operates two scientific large scale facilities for investigating the structure and function of matter: the research reactor BER II for experiments with neutrons and the synchrotron radiation source BESSY II. In the department of solar energy our scientists are working on the next generation of solar cells, including new kinds of materials and innovative cell structures. As cofounder of the Photovoltaic Competence Centre (PVcomB) HZB supports the technology transfer to the industry.
Description: The experimental set-up “CISSY” at the BESSY synchrotron combines X-ray emission spectroscopy (XES), X-ray absorption spectroscopy (XAS) and photoelectron spectroscopy (PES) with ex-situ, in-system and in-situ preparation of buffer and window layers for chalcopyrite solar cells. Depending on the excitation energy used, the information depth provided by these methods ranges from a few monolayers up to microns. Any type of thin films can be analyzed with regards to chemical, electronic and partly structural properties. The unique features of this analysis tool are the combination of state-of-the-art, synchrotron-based analytics with versatile layer preparation methods, a fast load-lock chamber with rapid sample turnover and large-area sample holders for sample sizes up to 25 x 25 mm2.
Description: The Electron Paramagnetic Resonance Facility at HZB (EPR@HZB) allows for the characterization of paramagnetic states such as many known defects in materials implemented in solar cells. One of the most prominent defects characterized by this technique are broken silicon bonds, (dangling bonds) in thin-film silicon, c-Si and mc-Si. The unique feature of the EPR analysis is that defects and impurities in semiconductor materials can be quantified at levels as low as 1013/cm3 depending on the specific nature of the paramagnetic specimen involved. The EPR signature allows a microscopic identification of the involved specimen through their characteristic EPR fingerprint. EPR@HZB has several spectrometers covering the microwave frequencies from 9 GHz up to 263 GHz with multi-frequency options such as ENDOR (Electron Nuclear Double Resonance). Typical samples sizes suitable for EPR measurements are 4 x 10 x 4 mm3.
TCO sputter-deposition and characterization
Description: The HZB maintains a central baseline window deposition and characterization effort as a service for the various groups doing in-house and project research on different chalcopyrite absorbers and buffer layers. The primary goal is to provide window layers with high throughput and reproducibility, fast sample return and full documentation.
Thermal deposition of molecular materials
Description: The Organic Solar Cells Group disposes of two facilities for thermal deposition of molecular materials either under vacuum or carrier gas conditions, respectively. In our laboratories there are glove boxes, laminar flow boxes as well as exhaust hoods for the wet chemical preparation of substrates under controlled conditions. Our equipment is specialized to process small molecules rather than polymers thus offering a service which is complementary to that of the Risoe group.