Microstructure, optical and electrical properties of CrAlN film as a novel material for high temperature solar selective absorber applications

The microstructure, optical and electrical properties of CrAlN and (Cr, Al) films synthesized by DC reactive magnetron sputtering method have been comparatively investigated. The results show that CrAIN film crystallizes in B1 NaCl-typed CrN structure with the preferred growth orientations of (111) and (220) and CrAIN grains show perfectly crystalline pyramid-like shape. The CrAlN film is determined as Al-doped CrN phase with the chemical formula of Cr0.9136Al0.0864N0.8999. It shows similar reflectance and absorptance characteristics to those of TiN based films in the solar spectrum region (300-2600 nm) and exhibits semiconductor nature with a sheet resistance of 38 k Omega/sq. Hence CrAlN can be used as a novel candidate material for high-temperature solar selective absorber coatings with good thermal stability and oxidation resistance. (C) 2014 Published by Elsevier B.V.