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脉冲激光沉积Sr缓冲Si表面的局部结构研究

Local structural studies of Sr-buffered Si surface prepared with pulsed laser deposition
课程网址: http://videolectures.net/ipssc2017_parkelj_structural_studies/  
主讲教师: Tjaša Parkelj
开课单位: 约瑟夫·斯特凡研究所
开课时间: 2017-05-23
课程语种: 英语
中文简介:
功能性氧化物与硅的成功集成可导致设计具有传感、逻辑和能量收集能力的多种新型电子设备。然而,硅表面是高度反应性的,需要通过适当的缓冲层进行钝化,该缓冲层具有化学稳定性,并且在结构上与过度生长的氧化层兼容。基于Si(001)上Sr½单层(ML)的缓冲层已证明满足这两项要求[1,2]。虽然这种表面通常是通过分子束外延(MBE)制备的,但克服其众多缺点的最有希望的技术之一是脉冲激光沉积(PLD)。在文献中可以找到大量MBE衍生表面的研究,但就我们所知,还没有对PLD制备的此类表面进行局部结构研究。然而,需要对缓冲层结构进行局部研究,以确保氧化物材料成功集成所需的高度有序的表面。 本文将介绍PLD制备的½ML Sr/Si(001)表面的扫描隧道显微镜(STM)分析结果。样品按照我们小组先前开发的程序制备[3],并使用超高真空手提箱转移,以确保STM测量所需的无吸附表面。大尺度STM图像证实了通过原位反射高能电子衍射测量检测到的(2×1)重构Sr/Si(001)表面。该重建完全覆盖了地表区域,并在相邻阶地上显示了两个等效的90°旋转区域。高分辨率图像显示沿[011]和[01̅1]方向运行的链状结构,横向距离为0.78。除了有序的链外,还可以区分大量的各种缺陷。然而,表面质量仍然与MBE制备的表面相当。本研究首次对PLD制备的Sr缓冲硅表面进行局部结构分析,并证实PLD可用于制备高质量缓冲层,该缓冲层是使用该技术在硅上实现复合氧化物外延生长所必需的。
课程简介: A successful integration of functional oxides with silicon could lead to the design of a wide variety of novel electronic devices with sensing, logic and energy-harvesting capabilities. However, the silicon surface is highly reactive, and needs to be passivated by an appropriate buffer layer that is chemically stable as well as structurally compatible with the overgrown oxide layer. A buffer layer based on ½ monolayer (ML) of Sr on Si(001) has been shown to fulfil both requirements [1,2]. While this surface has been conventionally prepared by Molecular Beam Epitaxy (MBE), one of the most promising techniques for overcoming its numerous shortcomings is Pulsed Laser Deposition (PLD). Plenty of studies for MBE-derived surfaces can be found in the literature, but to the best of our knowledge, there have been no local structural studies of such a surface when prepared by PLD. Nevertheless, a local study of the buffer layer structure is needed to assure a highly-ordered surface, required for a successful integration of oxide materials. In this contribution, the results of Scanning Tunneling Microscopy (STM) analysis of ½ ML of Sr/Si(001) surfaces prepared by PLD will be presented. The samples were prepared following a procedure previously developed by our group [3], and transferred using an ultra-high vacuum suitcase, in order to ensure an adsorbate free surface necessary for the STM measurements. Large-scale STM images confirm the (2×1) reconstructed Sr/Si(001) surface detected by in-situ reflective high-energy electron diffraction measurements. This reconstruction covers the surface area entirely, and exhibits two equivalent 90°-rotated domains on the neighbouring terraces. High resolution images reveal chain-like structures running along the [011] and [01̅1] directions with a lateral distance of 0.78. Apart from the well-ordered chains, an abundance of various defects can be distinguished. However, the quality of the surface is still comparable to the MBE prepared surfaces. This study represents the first local structural analysis of a PLD prepared Sr-buffered Si surface and confirms that PLD can be used for the preparation of a high quality buffer layer necessary for achieving epitaxial growth of complex oxides on silicon using this technique.
关 键 词: 脉冲激光沉积; 缓冲层结构; 复合氧化物
课程来源: 视频讲座网
数据采集: 2021-11-05:zkj
最后编审: 2021-11-05:zkj
阅读次数: 45