Hydrothermal Preparation And Piezoelectric Ferroelectric Properties Of NBT Nanostructures

As a kind of very important functional materials,low-dimensional ferroelectric nanomaterials play a very important role in people’s daily life due to their excellent properties.With the development of preparation technology of low dimensional nanomaterials,the research of one-dimensional materials has became a hot topic for scientific research enthusiasts.Barium titanate based lead-free piezoelectric materials are considered as the main alternatives to lead-containing materials due to their high Curie temperature and strong ferroelectric properties.As a new preparation method of oxide powder,hydrothermal synthesis has been widely used in the preparation of low-dimensional nanomaterials because of its convenient operation and high purity.Therefore,in this paper,Na0.5Bi0.5TiO3 lead-free relaxor piezoelectric powders with different morph ologies have been obtained by hydrothermal synthesis method,by optimizing the process parameters and controlling the formation and growth process of the crystal nucleus.Then the original morphology and domain structure of nanocrystals with different morphologies were observed by PFM.The Na0.5Bi0.5TiO3 nanowires with good ferroelectric and electrical properties were selected as the research object.Different electric fields were loaded into the micro-region of the nanowires.The domain flipping characteristics of the nanowires were systematically observed under the action of the applied electric field.Finally,NBT ferroelectric gate field effect transistors are fabricated,and the output and transfer characteristics of NBT ferroelectric gate field effect transistors are tested by semiconductor test system.The main research works are as follows.1.Firstly,we adopted the hydrothermal synthesis method in the research and synthesized the Na0.5Bi0.5TiO3 nanoparticles with different morphologies by optimizing the relevant process parameters.Then,the microstructure of Na0.5Bi0.5TiO3 nanoparticles was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscope(TEM).It is found that the concentration of mineral agent,reaction temperature and reaction time have significant effects on the morphology of powders.The growth conditions of Na0.5Bi0.5TiO3 nanowires are particularly harsh,which are affected by the mechanism of dissolution and recrystallization.2.The primary domain states of Na0.5Bi0.5TiO3 nano-powders with different morphologies were observed by PFM.Then the phase-voltage curves and amplitude-voltage curves of the three kinds of nano-powders were measured.The results show that the morphology of the Na0.5Bi0.5TiO3 nanowires is good,the"butterfly curve" is more symmetrical,and the hysteresis loop turns over 180°.3.The Na0.5Bi0.5TiO3 nanowires with good electric and ferroelectric properties were selected as the research object,and the domain reversal characteristics under different applied electric fields were observed.The results show that the applied electric field can make the ferroelectric domain flip 90°and 180°.4.We improved the traditional transistor structure by using ZnO nanowires as conductive channels to fabricate a NBT ferroelectric gate field effect transistor and test the output characteristics and transfer characteristics.Compared with traditional field-effect transistors,the fabrication is more convenient and more efficient.