PLD方法制备CaCu_3Ti_4O_(12)薄膜结构研究

Study on the structure of CCTO thin films fabricated by PLD

采用脉冲激光沉积法(PLD)分别在LaAlO3(100)以及MgO(100)基片上,在不同的沉积温度下,制备具有体心立方类钙钛矿结构的CaCu3Ti4O12(CC-TO)薄膜。在LAO基片上生长的CCTO薄膜,X射线衍射(XRD)分析表明沉积温度在680℃以上可以实现(400)取向生长,740℃薄膜可以实现cubic-on-cubic的方式外延生长。原子力显微镜(AFM)和扫描电子显微镜(SEM)分析分别显示CCTO薄膜的表面平整,界面清晰。后位的反射高能电子衍射(RHEED)观察到CCTO薄膜的电子衍射图谱,为点状。在MgO基片上,由于薄膜与基片较大的晶格失配,通过生长具有(100)和(110)取向的LaNiO3(LNO)缓冲层,诱导后续生长的CCTO薄膜随着温度的提高,由(220)取向生长转变成(220),(400)取向生长。

Body centered cubic provskite-related CaCu3Ti4O12（CCTO）thin films were fabricated on LaAlO3（100） and MgO（100） single crystal substrates at different temperature by pulsed laser deposition （PLD）, X-ray diffraction （XRD） scan indicated that （400）-oriented CCTO thin films were fabricated on LAO substrates above 680℃. Cubic-on-cubic epitaxial growth mode could be obtained at 740℃. Surface morphology of CCTO thin films was analyzed by atomic force microscopy （AFM）. A sharp interface between the CCTO thin film and the LAO substrate can be demonstrated by scanning electric microscopy （SEM）. The ex situ reflection high energy electric diffraction （RHEED） was used to get the electric diffraction pattern,which was spotty. Because of the high lattice mismatch between the MgO substrate and CCTO film,the buffer layer of （100） and （110）-oriented LNO was fabricated on MgO substrate. As the temperature increasing,CCTO films with （220） -oriented growth changed to （220） and （400）-oriented growth.