Ti was deposited on the Al substrate using DC magnetron sputtering with changing the N2 gas for the possible application of a solar absorbing layer. N2 gas ranged from 50 to 75 sccm was systematically applied in the 5 sccm interval and the variation of the absorption rate was investigated. Microstructural examination and elemental analysis indicate that Ti was reacted with N2 gas and formed TiNOx compound. As compared with the film without any exposure of N2 gas, absorption rate improved by more than 20%. Typically the average absorption of TiNOx fim with 65% of N2 gas was about 99% in the visible range, and the average absorption was more than 90% in the infrared absorption region respectively.
