Cluster tool for in situ processing and comprehensive characterization of energy materials at high temperatures

In situ processing and comprehensive characterization is essential for design and development of materials used and processed at high-temperatures. Here, a new cluster tool for processing and depth-resolved compositional, structural and optical characterization of layered
materials with thicknesses ranging from sub-nm to 1 μm at temperatures of -100 to 1000 °C is described [1]. The implemented techniques comprise
magnetron sputtering, ion irradiation, Rutherford backscattering spectrometry, Raman spectroscopy and spectroscopic ellipsometry. The combination of techniques enables sample processing by scalable, clean, waste-free, and industry-relevant technologies, quantitative depth-profiling for elements with Z ≥ 6, structural and chemical characterization, sensitivity and nm-precise thickness and optical information for single layers, multilayers and composites. In this study, the cluster tool was used for i) metal-induced crystallization with layer-exchange of a-Si/ Ag layer stacks, and ii) for hightemperature characterization of two types of solar-selective coatings for concentrated solar power (CSP), namely Al Ti (O N )-based single and multilayers [2, 3] and an n-type doped solar-selective transparent conductive oxide [4]. Starting with an a-Si/ Ag bilayer stack, metal-induced silicon crystallization with partial layer exchange occurs at 540 °C. The final stack is approximately described by the sequence crystalline Si (c-Si)/ Ag/ c-Si. All the layers contain minor fractions of the other element. Moreover, the Si volume fraction comprises approximately 10 % of amorphous Si. For the CSP coatings, no compositional and structural changes were found up to a maximum temperature of 840 °C in vacuum. Both types of solar-selective coatings thus represent promising materials for the next generation of CSP technology.
[1] R. Wenisch et al., Anal. Chem. 90, 7837-7824 (2018)
[2] I. Heras et al., Sol. Energy Mat. Solar Cells, 176, 81-92 (2018)
[3] R. Escobar-Galindo et al., Sol. Energy Mat. Solar Cells, 185, 183-191 (2018)
[4] F. Lungwitz et al., submitted (2018)
Financial support by the EU, grant No. 645725, project FRIENDS , and the HGF via the W3 program (S.G.) is gratefully acknowledged.