Surface study of the (4x1)/(1x4) structure of Anatase (001) films grown by PLD and MBE

The objective is to determine the (4x1) surface superstructure of an anatase-TiO2(001) film grown by PLD under UHV conditions. A similar experiment was already performed on BM32 (2020013 experiment). The measured set of fractional rods, consisting of a set of seven reflections, was not sufficient to allow us to discriminate between the models found in the literature. We requested beam time to take a new data set in BM32 with new films presenting surface terraces 5 times (500 nm) larger than those initially measured three years ago in 2020 in the same beamline (100 nm) [1]. The experiment will be used to compare these films with films prepared by MBE by enhancing the oxygen reactivity using an oxygen cracker during the growth process.本研究旨在确定在超高真空（Ultra-high vacuum, UHV）条件下通过脉冲激光沉积（Pulsed Laser Deposition, PLD）制备的锐钛矿相TiO₂(001)晶面薄膜的(4×1)表面超结构。此前已在BM32光束线站（2020013号实验）开展过同类实验，当时测得的一组包含7个衍射反射的分数衍射杆数据集，不足以区分文献中已报道的各类模型。为此我们申请了BM32光束线站的束流时间，计划制备表面平台尺寸为2020年该光束线站初始实验中测得的平台尺寸（100 nm）5倍（即500 nm）的新型薄膜，并采集新一轮实验数据集。本实验将用于对比本次制备的此类薄膜与通过在生长过程中加装氧裂解装置以提升氧气反应活性的分子束外延（Molecular Beam Epitaxy, MBE）制备的薄膜。