System for angle-resolved photoelectron spectroscopy

为了能够在电子学和光电子学的现代和新兴材料研究的前沿，应该获得一个高空间分辨率的角度分辨光电子能谱系统(µ-PES)。在这一研究领域特别令人感兴趣的是揭开所有相关长度尺度上的化学成分和电子性质，直到微米区域。集成的超高真空系统包括样品制备室和分析室，便于在高清条件下进行样品制备/制备，通过低能电子衍射(LEED)分析表面结构，使用X射线光电子能谱(XPS)确定表面化学计量比，以及利用角度分辨紫外光电子能谱(ARUPS)研究电子能带结构。该系统的一个关键特征是可以从定义的样点进行XPS和ARUPS测量，分析仪的显微镜功能使其能够选择小至几平方微米的区域。这一要求是当前和计划中的研究计划的结果，该计划涵盖了具有微米长度非均质性特征的材料。这与二维(2D)材料有关，例如过渡金属二卤化物、过渡金属碳化物和氮化物，以及通常以单层形式存在的共轭2D聚合物。研究计划的其他组成部分，即本征有机半导体和掺杂有机半导体，也具有必须在实验中识别和区分的空间差异。我们努力的总体目标是全面了解这些材料类的电子性质，这对评估它们在新型电子和光电子器件中的使用具有重要意义。将获得的系统大大增强了实验能力，能够探索新的研究领域，并丰富了我们目前和计划中的合作。

To enable research at the forefront on modern and emerging materials for electronics and optoelectronics, a system for angle-resolved photoelectron spectroscopy with high spatial resolution (µ-PES) should be acquired. Of particular interest in this research field is unraveling the chemical composition and electronic properties on all relevant length scales, down to the micrometer regime. The integrated ultrahigh vacuum system, comprising sample preparation and analysis chambers, facilitates sample fabrication/preparation under highly defined conditions, analyzing the surface structure by low energy electron diffraction (LEED), determining the surface stoichiometry with X-ray photoelectron spectroscopy (XPS), as well as investigating the electronic band structure with angle-resolved ultraviolet photoelectron spectroscopy (ARUPS). A key feature of the system is that XPS and ARUPS measurements can be performed from defined sample spots, where the microscopy function of the analyzer enables selecting areas as small as a few square-micrometers. This requirement is a consequence of the current and planned research program, which encompasses materials that are characterized by heterogeneity on the micrometer length scale. This pertains to two-dimensional (2D) materials, such as transition metal dichalcogenides, transition metal carbides and nitrides, as well as conjugated 2D polymers, all often in the monolayer form. Further components of the research program, i.e., intrinsic and doped organic semiconductors, also feature spatial variations that must be identified and distinguished in experiment. The overall aim of our efforts is obtaining a comprehensive understanding of these material classes' electronic properties, which significantly contributes to their evaluation for the use in novel electronic and optoelectronic devices. The system to be acquired substantially enhances the experimental capabilities, enables exploring new research fields, and enriches our present and planned cooperations.