Optical simulation and fabrication of HfMoN/HfON/Al2O3 spectrally selective coating

• Published in: Solar energy materials and solar cells 2015-09, Vol.140, p.328-334
• Main Authors: Selvakumar, N., Prajith, K., Biswas, A., Barshilia, Harish C.
• Format: Article
• Language: English
• Subjects: HfMoN; Optical constants; Reflectance; Spectrally selective coating; Spectroscopic ellipsometry
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2015.04.031

Detailed ellipsometric studies were carried out to measure the refractive indices (n) and extinction coefficients (k) of the HfMoN(H)/HfMoN(L)/HfON/Al2O3 tandem absorber in the wavelength range of 300–1000nm. The experimentally measured ellipsometric parameters have been fitted with simulated spectra using the Tauc–Lorentz model for generating dispersion of optical constants of the individual layers. Using these n and k values a three layer HfMoN/HfON/Al2O3 spectrally solar selective coating was designed and simulated using Essential Macleod software. The optical constants and thicknesses obtained from the simulation were used to develop the three layer tandem absorber with high absorptance and low emittance. The three layer tandem absorber has been deposited on stainless steel (SS) substrates using a magnetron sputtering system. The spectrophotometric data showed that the three layer tandem absorber exhibits high absorptance of 0.95 with low emittance of 0.14 on SS substrate and these values are similar to that of four layer HfMoN(H)/HfMoN(L)/HfON/Al2O3 tandem absorber. •Ellipsometric studies of HfMoN(H)/HfMoN(L)/HfON/Al2O3 coating were carried out.•Three layer HfMoN/HfON/Al2O3 tandem absorber was designed and developed.•The ellipsometric n and k values were used for the design and simulation.•Essential Macleod software was used for the design and simulation.•The three layer tandem absorber exhibited high α of 0.95 and ε of 0.14.