Study On The Preparation And Properties Of Light Recording And Ferroelectric Materials

The appearance of artificial film is an important sign of the material science development in the twentieth century. Films, film science and film technology have always been the most active research field and have already made a great and rapid progress since 1970s. In the field of optical recording, Cu₃N film was extensively studied for its low decomposition temperature, high electrical resistivity, and obviously reflectivity difference between Cu substance for infrared and visible light.Recently, a great deal of international attention has been focused on the preparation, properties and applications of ferroelectric thin films as functional information material and device. Ferroelectric thin film has many excellent physical properties and effects, such as ferroelectric-switch, piezoelectricity, pyroelectricity, electro-optic, acousto-optic and nonlinear-optic properties. Therefore, it has promising applications in the fields of micro-electronics, optical-electronics, integrated optics and micro-mechanical. The studies on PLT thin films are predominant of the ferroelectric materials.This thesis is made up of two parts. In the first part, the recent progress of write-once optical recording Cu₃N films, especially its applications, is introduced. The properties of pure and Ti-doped, Ni-doped and Sn-doped Cu₃N films were studied. In the second part, the recent progress and application fields of ferroelectric PLT films are introduced. The properties of PLT thin films and were preliminary studied.In our work, Cu₃N films, Ti doped Cu₃N films, Ni doped Cu₃N films and Sn doped Cu₃N films were prepared on glass substrate at room temperature using radio frequency magnetron sputtering method. The major content of this work were summarized as followings:1. Study on the preparation and properties of pure Cu₃N thin filmsIn this part, copper nitrides films were deposited in different nitrogen gas partial pressure (P_N2) at room temperature while maintaining the total flux 30 sccm. The numerical value of the P_N2 was 0 Pa, 0.2 Pa, 0.4 Pa, 0.6 Pa, 0.8 Pa and 1 Pa respectively. The relationship between crystal structure of Cu₃N films and P_N2 has been studied by X-ray diffractometer (XRD), which shows that when P_N2=0.6 Pa, the films crystallized well; The copper nitride films were prepared on glass substrates at room temperature by RF magnetron sputtering method under various RF sputtering power, 180W, 300W and 520W respectively. The relationship between crystal structure of Cu₃N films and RF power has been studied. The electrical properties of the Cu₃N films were investigated by UV-visible spectrum, four-point probe, atomic force microscope (AFM) and field emission scanning electron microscope (FE-SEM) methods. When the RF power is not lower than 180W, the films crystallized well and the preferential growth is along the [100] direction; The copper nitride (Cu₃N) films were deposited on glass substrate by RF reactive sputtering using different substrate-target distances, 24mm, 31.9mm, 40mm, 48.4mm and 55mm respectively, at room temperature. The changes of the surface morphology, optical and electrical properties of the Cu₃N films at the different substrate-target distances were also studied. Results indicated that when the deposition distance was less than 48mm, the films crystallized well.2. Study on the preparation and properties of doped Cu₃N thin filmsWe prepared the Ti-doped, Ni-doped and Sn-doped copper nitrides films in different sputtering atmosphere, gas flow rate and substrate temperature. The metal which doped in copper nitrides films was glued or enchase to the copper disc surface uniformly. The relationship between surface morphology, lattice constant, optical and electrical properties of Cu₃N films and metal-doped has been studied by several characterization technique. Results shows that the properties of films doped with Ti atoms did not change obviously, but the films doped with Ni, Sn atoms changed to semiconductor from insulator, and the optical energy band gaps diminished.3. Study on the preparation and properties of PLT thin filmsIn this article, we prepared (Pb_1-xLa_x)Ti_1-x/4O₃ (x=0.09) nanosized films on ITO/glass substrates using Sol-Gel method and spin-coating technology at lower temperture (600℃). The grain size of PLT thin film is about 30nm, the film surface is smooth and no crack, and there is only perovskite phase existed in the film. Metal ions were combined with C-0 bond in the thin films.