| ZnSe is an excellent one of all the infrared transparent materials used in the 0.7-14μm area,but its refractive index is relative high,its reflection loss is as high as 32％,and its mechanical properties such as wear and corrosion resistances are not satisfied when it is as infrared parts,therefore, it is very necessary for it to cover anti-reflective and protective films on its surfaces. The main aim of the thesis is to design such film system and to prepare these film system on ZnSe. Based on the theory of film optics and design method of the computer- assisted 'complete search', several kinds of anti-reflective and protective films suitable for ZnSe surfaces were designed. Based on the study of protective materials used in infrared field, the materials used in the film system were chosen. The film system is DLC/DLC/Ge1-xCx. The design scheme was at last decided according to the study in the materials for films, optical constant (mainly thickness and refractive index of the component film) and the deriation of optical constant of film system on transmittance. The advantage of this scheme is that its transmittance is less influenced by the error of the films thickness, hence the reproduction of such film system can be guaranteed.Based on the study in the techiques of film preparation and their comparison each other, aa well as a lot of experiments,t he technique of reactive mid-frequency magnetron co-sputtering with double targets was used to prepare the DLC/DLC/Ge1-xCx film system with infrared transmittance and protectice properties. The advantages of this techique comparing with radio-frequecy(RF) magnetron sputtering are as follows:1) The damage due to this technique to operators and environment is less than that due to RF one.2) The composition of DLC/Ge1-xCx can be easily controlled by this technique with double target (Ge and C targets) and hence, the ratio of CH4/CH4+Ar could be reduced by using C target the poison of the targets due to the formation of nonconducting film on the surface of the targets, therefore, can be avoided, which will harm to stabilization of sputtering, and affect the quality of the prepared films.3) DLC/Ge1-xCx with different carbon concentration can be prepared, in other words, different values of refractive index of the films can be controlled. while DLC/Ge1-xx films with high refractive index can be prepared by RF magnitron sputtering.According to the investigation of the publication, DLC/Ge1-xCx films system is firstly prepared with reactive mid-frequency magnetron co-sputtering. The prepared films were analysed to understand their structure, composition and optical constant. And systematic study were also done on the relation ship between the composition of the DLC/Ge1-xCx miasured with XPS analysis and the ratio of the CH4/CH4+Ar can be obtained; and the relationship between the composition of the film and refractive index can be obtained based on the optical constant (thickness and refractive index of the films according to the maximum method in spectral analysis; The effect of substrate temperature on the phase structure of the films can be checked by XRD and Raman spectra. On the basis of these analysed above, the technology parameters and film systems were selected and finally confirmed, and the DLC/Ge1-xCx film system with anti-reflective and protective films was produced on the both surfaces of ZnSe substrate, where its average transmittance in 0.7-14μm is as high as 80.3％,in other words, this film system cause ZnSe to incrense transmittance by about 15％.The main content and results in the thesis are as follows:1. Based on the theory of film optics and experimental results in our work, a computer-assisted 'complete search' was selected to design our film system on ZnSe substrate with anti- reflective property; base on the demand for the protection of ZnSe, several materials were selected, and hence the parameters of film system were also determined.2. Based on the design scheme, several film systems were selected and experimentally studied with different preparetion methods. At last, a technique of the reactive mid-frequency magnetron co- sputtering with double targets to be used to prepare DLC/Ge1-xCx film system was obtained.3. Ge1-xCx film system deposited on ZnSe with this method with different carbon concentration can be satisfied the demand of different refractive index of design scheme, apart from this, This deposition method can avoid the poison of target, hence, can realize stable operation during film preparation.4. Systematic reaearch in the preparation of Ge1-xCx films with our method, a varies of analyses on the structure, composition and optical constant of the films, as well as study in the relation ship between the preparation technologies and those analyses,. The optimum tehcnology parameters have been obtained. The film system with excellent properties has been prepared with this technology. And the reproduction of such film system can also be guaranted with this technology.5. .ZnSe deposited with DLC/Ge1-xCx film system on its both surfaces has average transmittance of 80.3％in the area of 0.7-14μm waveband. This means that the whole transmittance of ZnSe is increased to 15％by such a film system. In addition, the coated ZnSE has a better resistant wear and corrosion based on the wear and corrosion experimental results. |
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