The purpose of this study, using high vacuum sputtering machines, is to sputter multi-layer of aluminum nitride composite layer (AlNx) for the solar selective absorbing film. Using UV spectroscopy, gloss meter, thermometer, etc. to explore features of AlN under different wattage deposited composite layer (AlNx) . The study found that if the interference of light through the glass before exposure to the AlN compound layer (AlNx), the thermal rise rate than direct exposure to light to the composite layer of aluminum nitride (AlNx) significantly improved, its efficiency by up to 9 %
