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HZB-UHV-end station for preparation and analysis of thin films for PV at BESSY II (CISSY)

[Cheetah Partner]

Preparation of samples and surface
Interface characterization of thin film solar cell components by x-ray based spectroscopy using synchrotron radiation and x-ray lab sources.

Technical Info

MAIN FEATURES:

The experimental set-up “CISSY” at the BESSY II synchrotron is regularly used for the characterization of chalcopyrite solar cells and their components, for surface analysis of silicon and compound semiconductor samples and has also found applications in related fields like thin film, battery materials or organic solar cells.“CISSY” combines

X-ray emission spectroscopy (XES)
X-ray absorption spectroscopy (XAS)
photoelectron spectroscopy (PES)

with ex-situ, in-system preparation of buffer and window layers for chalcopyrite solar cells by utilizing different depostion technique (sputtering, MOCVD, e-beam, ALD, etc).

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 with rapid sample turnover and large-area sample holders for sample sizes up to 25 x 25 mm2.

LIMITATIONS OR CONSTRAINTS:

No in-situ preparation inside the analytical UHV chamber. The energy range for the CISSY set-up is 20-2000 eV while with a different end-station at BESSY II 2010 eV to 10 keV can be used. For PES, moderately conducting samples are needed

TYPICAL SERVICES OR RESULTS:

Typical applications are

Surface characterization (elemental composition, purity, compounds, work function, valence band position)
Interface characterization (interdiffusion, chemical reactions)

Examples of its utilization are:

the examination of a copper gradient in chalcopyrite solar absorbers
the examination of in-system sputtered Zn(O,S) buffer layers and wet-chemically deposited CdS

Participation to Research Projects:

Apart from HZB Research group at the Institute for Heterogeneous Materials, numerous other groups in the field of thin film PV are involved in using this equipment, mainly from research institutions in Germany but also from the PV industry and from partners in Spain, Switzerland, France, the Czech Republic and the US. Within a recent European research project (ATHLET) HZB has collaborated with researchers from several European and countries, examining e.g. buffer, layer composition, interdiffusion or surface modifications