RUI: Electronic Properties of Finite Molecular Layer Transition Metal Dichalcogenides

非技术：该项目的目标是更好地理解厚度在几个原子层范围内的薄材料的电子和光学特性。这些特性在太阳能电池、发光二极管（led）和各种传感器中都有实际应用。一种多学科的方法被用来获得在这些应用中使用这些材料所必需的更完整的画面。这项研究涉及到接受过电子、光学和化学等多种技术训练的本科生。这样的环境造就了全面发展的学生，为工业界或学术界的职业生涯做好了准备。北爱荷华大学为该项目提供了一个极好的机会，可以对爱荷华州及周边各州不同背景的小学、初中和高中学生产生积极影响。与高中科学教师的定期接触，可以直接展示教师的研究活动和学生的机会。这些努力鼓励学生探索STEM（科学、技术、工程和数学）领域的职业。技术：该项目的目标是对各种有限层二硫化物分子片的电子和光学特性有更深入的了解。超声波搅拌被用来将这些层状晶体从大块中分解成薄的纳米片。那些层数最少的薄片使用离心机分离，并使用扫描隧道显微镜、光谱学和弹道电子发射显微镜进行研究。扫描隧道显微镜测量服务于研究拓扑特征以及表面电学性质的原子尺度。这包括与二维二硫化物片中的电荷密度波相关的零电阻特性。拉曼和光致发光补充了使用扫描隧道显微镜的局部探针进行的电测量，提供了电子能带结构和振动特性的全局信息。传输测量是通过使用弹道电子发射显微镜向这些结构中注入电子来实现的，从而可以表征电子散射作为温度和能量的函数。总之，这些组合的数据将使我们能够更全面地了解各种材料系统中电子特性的降维。更重要的是，将该领域的研究重点扩大到更多样化的层状材料阵列将增强我们对二维系统中基础物理的理解。修改现有的理论，以涵盖更广泛的层状材料，导致更强大的理论模型，必不可少的设备设计。

Non-Technical: The goal of this project is to better understand the electronic and optical properties of thin sheets of materials with thickness in the range of a few atomic layers. These properties have practical applications in solar cells, light emitting diodes (LEDs), and a wide variety of sensors. A multidisciplinary approach is used to obtain a more complete picture necessary to use these materials in these applications. This research involves undergraduate students trained on a wide variety of techniques that involve electronics, optics and chemistry. Such an environment results in well-rounded students ready for careers in either industry or academia. The University of Northern Iowa provides an excellent opportunity for this project to have a positive impact on elementary, middle, and high school students from diverse backgrounds throughout Iowa and surrounding states. Regular contact with high school science teachers allows faculty research activities and student opportunities to be showcased directly. Such efforts encourage students to explore careers in STEM (science, technology, engineering, and mathematics) fields. Technical: The goal of this project is to develop a more thorough understanding of the electronic and optical properties of a wide variety of finite layer dichalcogenide molecular sheets. Ultrasonic agitation is used to break apart these layered crystals from the bulk into thin nano-sheets. Those sheets with the smallest number of layers are separated using a centrifuge and studied using scanning tunneling microscopy, optical spectroscopy, and ballistic electron emission microscopy. Scanning tunneling microscopy measurements serve to study topological features as well as surface electrical properties on the atomic scale. This includes the zero resistance characteristics associated with charge density waves in two-dimensional dichalcogenides sheets. Raman and photoluminescence complement the electrical measurements made using the localized probe of the scanning tunneling microscope, providing global information on electronic band structure and vibrational properties. Transport measurements are achieved by injecting electrons into these structures using ballistic electron emission microscopy, allowing characterization of electron scattering as a function of temperature and energy. Together, these combined data will enable a more complete understanding of reduced dimensionality on the electronic properties in a wide variety of material systems. More importantly, broadening the research focus of this field to a more diverse array of layered materials will enhance our understanding of the fundamental physics in two-dimensional systems. Modifications of current theories to encompass a wider variety of layered materials leads to more robust theoretical models, essential to device design.