Development of highly functionalized diamonds and their application to micro-reactor systems for special circumstances

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Diamond possesses unique physico-chemical characteristics including a large band gap and small heat capacity, and therefore has potential for numerous applications in a wide variety of areas. If modification of the surface of such diamonds with functional groups is achieved, diamonds would be expected to be quite unique sensors as well as micro-reactors. In this project, boron-doped diamond films were successfully synthesized on an indium substrate by a microwave plasma assisted chemical vapor deposition(MPCVD) method and were functionalized with amination after chlorination with chlorine.In order to synthesize a highly orientated diamond films, the iridium substrate was bais-treated by the constant-current mode to permit the formation of oriented diamond nuclei. As a result, the Hall mobility was closely related to the surface morophology of the diamond films. A Holl mobility of 340cm^<-2> V^<-1> s^<-1> and hole concentration of 2 x 10^<10> at 250 K was obtained for the hetroepitaxial boron-doped diamond film synthesized at a B/C ratio of 200ppm.A synthetic diamond powder was chlorinated with pure chlorine gas in a tube by irradiation with ultraviolet light. Then the resulting chlorinated diamond powder was aminated by pure ammonia gas at different temperature. As a result, formation of NH_4^+ on the surface of the diamond powder treated at room temperature was verified by diffuse reflectance infrared transform(DRIFT) spectroscopy. Amination at 373 K showed DRIFT peaks corresponding to C=N vibration and NH_2 scissoring. Most of nitrogen on the surface was present as imines, when amination was performed at 573K