Biyosensör uygulamaları için karbon nanotüplerin sentezi ve karakterizasyonu üzerine araştırmalar

In this thesis, production optimizations of CNTs were carried out with the CVD method, which is a practical and cost-effective method. In the CVD method, a cause-effect relationship was established between the properties and process parameters that determine the final morphology, such as substrate type, catalyst type, catalyst concentration, growth time, and processing temperature. In the first stage, five different catalysts, four different substrate types, three different growth times, three different catalyst concentrations, and three different growth times were applied. As a result, the most efficient tubular performance was obtained on the Si wafer substrate at one thousand degrees Celsius processing temperature by applying growth times of three, five, and seven minutes with the help of iron-based catalysts. Data from SEM samples showed that the lowest tube diameter was acceptable nanoscale. With EDX analysis, it has been shown that as the catalyst concentration increases, the carbon efficiency decreases, confirming the results of the SEM analysis. The highest carbon percentage was determined in the sample with the lowest catalyst concentration. The specific peak attributed to sp2 hybridization of CNT carbon in FT-IR analysis was observed in all sample. CNTs, which are targeted for use in biosensor applications, are desired in terms of their high defect structure and faster interaction with chemical and bioactive species. The Raman spectra confirmed that this goal was achieved with the I_D/I_G ratio of the obtained CVD-based CNTs. XRD graphs showed that the expected graphitic peak for an ideal CNT was obtained for all samples. In XPS spectra, it was observed that the sp3/sp2 ratio increased with increasing catalyst concentration. The current-voltage characterizations revealed that all measurements were close and consistent, as well as high potential in a biosensor application. As a result, it has been proven that the properties of CNTs, which are the output of this thesis, can be improved for use in biosensors by controlling the production parameters. In this thesis, production optimizations of CNTs were carried out with the CVD method, which is a practical and cost-effective method. In the CVD method, a cause-effect relationship was established between the properties and process parameters that determine the final morphology, such as substrate type, catalyst type, catalyst concentration, growth time, and processing temperature. In the first stage, five different catalysts, four different substrate types, three different growth times, three different catalyst concentrations, and three different growth times were applied. As a result, the most efficient tubular performance was obtained on the Si wafer substrate at one thousand degrees Celsius processing temperature by applying growth times of three, five, and seven minutes with the help of iron-based catalysts. Data from SEM samples showed that the lowest tube diameter was acceptable nanoscale. With EDX analysis, it has been shown that as the catalyst concentration increases, the carbon efficiency decreases, confirming the results of the SEM analysis. The highest carbon percentage was determined in the sample with the lowest catalyst concentration. The specific peak attributed to sp2 hybridization of CNT carbon in FT-IR analysis was observed in all sample. CNTs, which are targeted for use in biosensor applications, are desired in terms of their high defect structure and faster interaction with chemical and bioactive species. The Raman spectra confirmed that this goal was achieved with the I_D/I_G ratio of the obtained CVD-based CNTs. XRD graphs showed that the expected graphitic peak for an ideal CNT was obtained for all samples. In XPS spectra, it was observed that the sp3/sp2 ratio increased with increasing catalyst concentration. The current-voltage characterizations revealed that all measurements were close and consistent, as well as high potential in a biosensor application. As a result, it has been proven that the properties of CNTs, which are the output of this thesis, can be improved for use in biosensors by controlling the production parameters.