Studies On Properties And Application Of Hydrogenated Carbon Films Containing Amino-Group

Doping or alteration components of materials is one of important approaches to remake and conquer nature. It is also an important method to improve the properties of materials, to enable materials to have new functions and to obtain the new materials as well. To fulfile some particular requirements, new materials possessing peculiar function, or oplimizing components and structure of materials to control properties of materials in order to obtain new application, are frequently developed and designed by human beings.The method of amino梘roup doping into hydrogenated amorphous carbon (ct-C:H) film and the influence of technological condition on it had been exhaustedly discussed in the article. The ci~-C:H film was prepared by the means of plasma assistance chemical vapor deposition with hydrocarbon n-butylamine (CH3CH2CH2CH2NH2) as carbon source. The material of carbon source was carried into chemical vapor deposition chamber under pure hydrogen. Acted by the accelerated electrons, the materials of carbon source were taken the form of plasma in the chamber. In the plasma system, there were C2H2 and CH3~, the material source to produce carbon film. There also was some amino-group in the plasma atmosphere. Hence the amino-group could be combined into network structure of cL-C:H in the deposition process.The foundational properties of amino-group doping hydrogenated carbon film such as components, density, structure and so on were measured and studied. The result indicated that the deposition reaction of amino-group doping was a kind of hydrogen escaping reaction, whose film was made from carbon, hydrogen and nitrogen. The content of carbon in the film increased with the increase of deposition power, while the contents of hydrogen and nitrogen decreased with deposition power. The density of film was in its range from 1.280g. cm~3 to 1.386g. cm3 and it would increase with the increased deposition power. The IR spectrum showed that there existed amino-group in the network structure of ctC:H film decreased along with the increase of deposition power. The analysis ofLR and Raman spectrum indicated that the amino-group doping cL-C:H films deposited at low power had possessed completely disorder structure. But the disorder degree of structure decreased alongside the increase of deposition power. The structure of films deposited at higher power was found to be a mixture structure of amorphous, graphite and diamond with diamond-like stucture.The mass sensitive properties of ct-C:H films containing amino-group to organic vapors were studied too. Measurement to a series of organic vapors indicated that the films possessed fine response properties to carboxyl acid vapors. In carboxyl acid material vapors, the films had the highest sensitivity to the formic acid vapor. The influence of deposition conditions and the coating mass on the response of the films were also considered. The determination lower limit of films to formic acid vapor was measured and it attained PPm grade. The experiment showed that the sensors coated a-C:H film as sensitive coating had the following characteristics of high sensitivity, good reproducibility, high stability, rapid response time and long useful life to formic acid vapor. The response mechanism of the film to organic vapors was discussed primarily. It is thought that the film reacted with molecule of carboxyl acid vapors through both the basicity hydrogen-bond of amino-group and the acid hydrogen-bond of carboxyl acid molecule. The interaction between sensitive coatings and formic acid vapors was the strongest in the carboxyl acid material vapors, so that the ct-C:H film containing amino-group was the most sensitive to formic acid.Furthermore, the response properties of the film to hydrogen (Hi) ion was also studied. Amino-group doping ci-C:H film showed good response to H~ ion in strong sulfuric acid solution. In O.5-~-3mol/L sulfuric acid solution, the sensitivity exhibited linear response with slope of 66mvIpH. The response of film to H~ ion was not disturb...