EAPSI: Synthesis and Electrical Transport Properties of Chemical Vapor Deposited Two-Dimensional Semiconductor Layers of Tungsten Diselenide

改进和提高硅技术是纳米技术和材料科学领域目前面临的挑战。在这方面，对厚度等于几个原子层的新型材料的研究，例如过渡金属二卤化物，可能导致一些电子和光电子应用的突破性解决方案。这些先进纳米材料的合成和电传输特性可以在广播接收器和无线通信等电子领域的各种数字和模拟电路中带来潜在的改进。在本项目中，将制备二硒化钨(WSe2)的二维原子层，并对其结构和电学性质进行表征。这项研究将在中国科技大学国家同步辐射实验室李嵩教授的指导下进行，这将提供与一位在最先进的实验室设施(如微电子设备纳米制造净化室)方面的知名专家合作的机会。二维纳米材料由于其电子性质、表面均一性以及能够以各种不同的方式进行官能化和掺杂而引起了人们的特别兴趣。特别是，原子薄的WSe2具有相对较高的载流子迁移率和直接带隙，不同于石墨烯S的零带隙。化学气相沉积法可以通过微调生长参数来研究合成WSe2层的方法。利用包括高分辨率电子显微镜和拉曼光谱在内的一系列方法，可以对WSe2薄膜进行物理和形貌表征。然后，我们将研究这些器件的各种电学和光学输运性质，如场效应、载流子迁移率和光电性质。该项目将分析分层和电传输特性之间关系的确切性质，并使人们能够以新的视角了解单层WSe2作为金属-氧化物-半导体场效应晶体管在电子纳米器件应用中的集成。该NSF EAPSI奖支持一名美国研究生的研究，并与中国科技部合作提供资金。

Efforts to improve and enhance silicon technology is a present challenge in the field of nanotechnology and materials science. In that respect, the investigation of novel materials that can be produced with thickness equal to a few atomic layers, for example transition metal dichalgoenides, might lead to breakthrough solutions for several electronic and optoelectronic applications. The synthesis and electrical transport properties of these advanced nanomaterials can lead to potential improvements in a wide variety of digital and analog circuits in electronics, such as broadcast receivers and wireless communications. In this project, two dimensional atomic layers of tungsten diselenide (WSe2) will be prepared and characterized structurally and electrically. This research will be carried out under the mentorship of Professor Li Song at the National Synchrotron Radiation Laboratory at the University of Science and Technology of China, offering an opportunity to work with a noted expert in state-of-the-art laboratory facilities such as a cleanroom for microelectronic device nanofabrication. 2D nanomaterials have become of particular interest given their electronic properties, surface homogeneity, and their ability to be functionalized and doped in a variety of different ways. In particular, atomically thin WSe2 is known to exhibit a relatively high charge carrier mobility and a direct band gap, unlike graphene?s zero band gap. The chemical vapor deposition method to synthesize layers of WSe2 can be investigated by fine-tuning the growth parameters. Using an array of methods, including high-resolution transmission electron microscopy and Raman spectroscopy, the WSe2 thin films can be physically and morphologically characterized. Then, various electrical and optical transport properties, such as the field effect mobility of charge carriers and photoelectronic properties, of these devices will be investigated. This project will analyze the exact nature of the relation between layering and electrical transport properties and enable new insight into the integration of monolayered WSe2 as metal-oxide-semiconductor field effect transistors in electronic nanodevice applications. This NSF EAPSI award supports the research of a U.S. graduate student and is funded in collaboration with the Chinese Ministry of Science and Technology.