高分子辅助沉积法(PAD)制备LaBaCo_2O_(5+δ)薄膜的研究

Growth of La Ba Co_2O_(5+δ) thin films on Si(001) substrate by polymer-assisted deposition technique

用高分子辅助沉积法在Si（001）基底上以SiO2为缓冲层成功地制备出LaBaCo2O5＋δ（LBCO）薄膜。X射线衍射谱证明了LBCO/Si（001）薄膜是（111）择优取向的单相赝立方结构。从LBCO薄膜样品的SEM照片可以看出,LBCO薄膜的晶粒大小并不均匀,其大的晶粒尺寸为1-2μm,小的晶粒尺寸为0.1-0.2μm;同时,可以明显观察到一些小的空隙,这些空隙有利于氧气的吸附及扩散。在LBCO薄膜的电阻（R）-温度（t）曲线测试中,电阻随温度的升高先急剧下降后缓慢下降,表明LBCO薄膜具有典型的半导体材料性质。LBCO薄膜在纯氧和空气中电阻的最低值分别为36Ω和382Ω,前者为后者的1/10,说明LBCO薄膜对氧气具有敏感性。

The La Ba Co2O5＋δ（LBCO） thin films were deposited on Si（001） substrate with an amorphous Si O2 buffer layer by the polymer-assisted deposition technique. Microstructures were examined by X-ray diffraction（XRD） technique,which confirmed the LBCO thin films present a single phase pseudo-cubic structure. From the SEM images of LBCO thin films, it can be seen that the grains（cluster） size of LBCO thin films were not uniform. The size of the biggest grain is 1-2μm and the size of the smallest grain is 0.1-0.2 μm. Simultaneously, the interspace between grains is obvious from SEM images, which is favorable to the adsorption and diffusion of oxygen. The resistance decreases sharply first then declines slightly as the increase of test temperature in the resistor（R）- temperature（t） test of LBCO thin film, indicating that LBCO thin film has a typical semiconductor material property. The lowest resistance values of LBCO thin films in pure oxygen and air environment are 36Ω and 382Ω, respectively. The former value is only 1/10 to the latter, which indicates that LBCO thin films are sensitive to oxygen.