The Preparation Of TiN_x Buffer Layer And Its Effect On The Field Emission Of One-dimension SiC Nanomaterial

Recently TiN films were extensively investigated due to its high intensity, high hardness, high melting temperature, high chemical stability, resistance to abrasion and high thermal and electrical conductivity .What is more, the films can be used to enhance the light emission of some material and change the band gap of material. One-dimensionial SiC nanomaterials also attracted a great deal of interest and became the first choice for the cathode material of the field emission because of the well thermal and chemical stability, high thermal conductivity, high breakdown field strength, low work function and excellent mechanical property. In this thesis, TiN_X films prepared at different conditions were used as the buffer layer to enhance the field emission of the one-dimensionial SiC nanomaterials.In my thesis, we studied the following aspect:(1) The effect of the different processing parameters on the microstructure and the electric properties of TiN_X films were studied. The results showed that, with the increase of the sputtering power, the film thickness increased firstly but subsequently decreased, and the atom ratio of N and Ti as well as the electrical resistivity always decreased. With an increase of the sputtering pressure, the film thickness decreased. The orientation of film was changed from (111) to the (200). The atom ratio of N and Ti and electrical resistivity also increased. With elevating the substrate temperature, the orientation of film was changed from (111) to (200). The dimension of the columnar crystal increased, but subsequently decreased. The atom ratio of N and Ti increased but electrical resistivity decreased.(2) The effects of the preparing condition on growing of one-dimensionial SiC nanomaterials were studied. The results showed that, the particle size of Ni catalyst decided the diameter of CNTs. The orientated growth of CNTs was the result of the induction of electric field, and the auto-bias played an important role on it. Under the same deposited condition, the diameter and length of CNTs grown on the TiN_X buffer layer with different microstructure was about 70nm and 1μm, respectively. The one-dimensionialial SiC nonamaterials was obtained after sputtered by Si and annealed at high temperature subsequently. The XPS result showed that there was strong Si-C bond in materials, and the XRD result showed that the material was SiC, which indicated that the one-dimensionial SiC nanomaterials can be ontained by CNTs template. From the SEM measurements, it can be seen that the one-dimensionial SiC nanomaterials deposited on SiO₂ buffer layers were more order but scanty compared with those deposited on TiNx buffer layers.(3) The effect of TiNx buffer layer on one-dimensionial SiC nanomaterial was studied. The results showed that TiNx buffer layer can remarkably affect the field emission of one-dimensionial SiC nanomaterials. When the substrate temperature increased, the atom ratio of N and Ti also increased. At the same time, the field emission became stronger. When the substrate temperature was 100℃, the field emission was the strongest, its turn-on field and threshold field was 9.0V/μm and 12.3V/μm, respectively. However, the turn-on field and threshold field of one-dimensionial SiC nonamaterial deposited on SiO₂ buffer layer was 17.8 V/μm and 21.6 V/μm, respectively. The TiN_X buffer layer can enhance the field emission of the one-dimensionial SiC nonamaterials compared with the SiO₂ buffer layer. These results are worth for the exploitement of the SiC field emission device.