System for angle-resolved photoelectron spectroscopy

为了能够在电子和光电子学的现代和新兴材料的最前沿进行研究，应该获得具有高空间分辨率的角分辨光电子能谱（µ-PES）系统。在这一研究领域特别感兴趣的是解开所有相关的长度尺度上的化学成分和电子性质，下至微米制度。集成的真空系统，包括样品制备和分析室，便于在高度限定的条件下进行样品制造/制备，通过低能电子衍射（LEED）分析表面结构，用X射线光电子能谱（XPS）确定表面化学计量，以及用角分辨紫外光电子能谱（ARUPS）研究电子能带结构。该系统的一个主要特点是可以从定义的样品点进行XPS和ARUPS测量，其中分析仪的显微镜功能可以选择小到几平方微米的区域。这一要求是当前和计划的研究计划的结果，其中包括以微米长度尺度上的异质性为特征的材料。这涉及二维（2D）材料，例如过渡金属二硫属化物、过渡金属碳化物和氮化物，以及共轭2D聚合物，所有这些通常都是单层形式。研究计划的其他组成部分，即，本征和掺杂的有机半导体也具有必须在实验中识别和区分的空间变化。我们努力的总体目标是全面了解这些材料类别的电子特性，这将大大有助于评估它们在新型电子和光电器件中的应用。该系统将大大提高实验能力，使探索新的研究领域，并丰富我们目前和计划的合作。

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.