Abstract :
Normalized dc conductivity was used to analyze the inhomogeneously graded depth profile structure of deposits
from dc magnetron reactive sputtering in a roll coater. The graded coating was obtained by moving the substrate
through the deposition zone with a non-uniform oxidation along the zone mainly due to the asymmetrical position
of the oxygen inlet to the right of the target. With this arrangement, the composition of the deposited film was gradually
changed from metal to metal oxide as the substrate moved from left to right through the zone. The profile control therefore
relied on the non-uniform oxidation along the sputtering zone. The study shows that the normalized dc conductivity
of stationary samples in this roll coater offers a simple and effective method to optimize the graded composition in
spectrally selective solar absorber coatings. A solar absorptance of 0.91 with thermal emittance of 0.05 at 100 C was
achieved for a single graded film without antireflection treatment.
2004 Elsevier Ltd. All rights reserved.
