TiO_(2)薄膜的相结构调控与表征

Phase structure regulation and characterization of TiO_(2) thin films

本文利用脉冲激光沉积技术在LaAlO;(001)衬底上生长了单晶锐钛矿和双相TiO_(2)薄膜,并利用X射线衍射和透射电子显微术对薄膜的显微结构进行了系统表征。单晶锐钛矿薄膜在LaAlO;(001)衬底上实现了外延生长,双相TiO_(2)薄膜以单晶锐钛矿TiO_(2)为基体,在其中夹杂着金红石TiO_(2)颗粒。TiO_(2)薄膜的相结构可通过调整靶材与衬底的间距来调控,远靶基距(150 mm)利于单晶锐钛矿薄膜生长,近靶基距(50 mm)易获得双相TiO_(2)薄膜。锐钛矿TiO_(2)电镜样品在离子减薄过程中易发生表面还原,导致电镜观察中出现莫尔条纹。研究表明30%H_(2)O_(2)浸泡可有效去除离子减薄样品表面的损伤层,防止莫尔条纹的出现。

In this paper,single-crystal anatase and dual-phase TiO_(2)thin films were grown on LaAlO;(001) substrates by pulsed laser deposition.The microstructures of the as-prepared thin films were systematically characterized by X-ray diffraction and transmission electron microscopy.Single-crystal anatase thin films were epitaxially grown on LaAlO;(001) substrates,and dual-phase TiO_(2)thin films were composed of the single-crystal anatase TiO_(2)matrix and numerous embedded rutile particles.The phase structure of the TiO_(2)thin films can be adjusted by changing the target-substrate distance.The long target-substrate distance(150 mm) is conducive to the growth of single-crystal anatase films,while the short target-substrate distance(50 mm) promotes the formation of dual-phase TiO_(2)films.TEM samples of anatase TiO_(2)are prone to surface reduction during the ion thinning process,resulting in the appearance of moiré fringes in TEM observations.It is revealed that 30% H_(2)O_(2)immersion can effectively remove the damage layer on the surface of the ion-thinned sample and prevent the appearance of moiré fringes.