Application of GexC1_(x)films to design and deposition of infrared antireflection and protection films

GexC1-x films were deposited by RF magnetron reactive sputtering. Its refra ctive index can vary between 1.6 and 4.0. Different thicknesses of GexC1-x antireflective films with GexC1-x as homogeneous and inhomogeneous films we re designed. Homogeneous GexC1-x antireflective films were deposited on ZnS substrates. The design results show that GexC1-x have high efficiency in a narrow band as homogeneous antireflective and protective films ; and in a wide band as inhomogeneous antireflective and protective films. With the in crease of film thickness, the transmittance curve of homogeneous antireflec tive films becomes very oscillatory, while the transmittance curve of inhom ogeneous antireflective films becomes relatively smooth and extended along long wavelength. The experiment results show that the transmittance of ZnS coated with homogeneous antireflective GexC1-x films can reach 90.4% (8 sim ilar to 11.5 mu m), 16. 5% higher in transmittance than uncoated ZnS sample with 73.9% in transmittance.