Paulidou Anastasia, Nix Roger M
Department of Chemistry, Queen Mary, University of London, London, UK E1 4NS.
Phys Chem Chem Phys. 2005 Apr 7;7(7):1482-9. doi: 10.1039/b418693a.
Ultra-thin films of zirconia have been prepared on a Cu(111) substrate using two different growth methods and characterised by a range of surface analytical techniques. The first method employed zirconium tetra-tert-butoxide [Zr(OC(CH3)3)4] as a precursor which was contacted with the heated substrate surface under high vacuum conditions to produce the oxide in a CVD-type process. TPD, MBS and XPS studies reveal that the precursor is readily adsorbed and decomposes rapidly at substrate temperatures above ca. 550 K to give stoichiometric ZrO2, and predominantly methylpropene and water vapour as gas phase by-products. The second method for oxide film growth involved the vacuum evaporation and oxidation of zirconium metal. Conversion to ZrO2 was achieved using high oxygen exposures and annealing at elevated temperatures to ensure complete oxidation of the base metal. Both methods produce zirconia films on the Cu(111) substrate which are thermally stable in vacuum up to ca. 923 K, and only start to degrade rapidly for temperatures in excess of 1073 K. After annealing at 923 K, LEED showed the zirconia to exhibit long-range ordering with a unit cell indicative of the growth of (111)-oriented cubic zirconia.
已使用两种不同的生长方法在Cu(111)衬底上制备了氧化锆超薄膜，并通过一系列表面分析技术对其进行了表征。第一种方法使用四叔丁醇锆[Zr(OC(CH3)3)4]作为前驱体，在高真空条件下使其与加热的衬底表面接触，通过化学气相沉积（CVD）型工艺生成氧化物。程序升温脱附（TPD）、分子束散射（MBS）和X射线光电子能谱（XPS）研究表明，前驱体易于吸附，并在高于约550 K的衬底温度下迅速分解，生成化学计量比的ZrO2，气相副产物主要为甲基丙烯和水蒸气。第二种氧化膜生长方法涉及锆金属的真空蒸发和氧化。通过高氧暴露和在高温下退火实现向ZrO2的转化，以确保贱金属完全氧化。两种方法都在Cu(111)衬底上生成氧化锆膜，这些膜在真空中热稳定性高达约923 K，并且仅在温度超过1073 K时才开始迅速降解。在923 K退火后，低能电子衍射（LEED）显示氧化锆呈现长程有序，其晶胞表明生长的是(111)取向的立方氧化锆。
