Monolayer Nucleation and Passivation of Advanced Electronic Materials

技术描述：原子层沉积是一个循环化学过程，提供亚纳米层厚度控制。第一层的键合是提供低缺陷界面的关键步骤，这使得原子层沉积在每个单元胞内成核。该项目通过结合扫描隧道显微镜和扫描隧道光谱学，对沉积在两种非常不同的半导体材料氮化镓和石墨烯上的氧化物单层进行原子层理解。这些材料的表面具有非常低的化学反应性，使制造独特的电子设备成为可能；然而，这些材料缺乏能与原子层沉积前体紧密结合的活性原子。对于石墨烯，非活性表面通过吸附有序单层有机配位配合物而被功能化，而对于氮化镓和有序层无机官能团沉积。发展了两种具有广泛适用性的技术：(a)超高真空横截面开尔文探针力显微镜，用于在纳米尺度上成像工作电容器和场效应晶体管内部的静电电位；(b)非接触式超高真空变频电容电压，用于现场测量栅极氧化物缺陷。非技术描述：目前，计算机芯片的速度和性能受到散热的限制。进一步提高性能需要降低电源电压以稳定单位面积的散热。该研究项目旨在开发纳米级绝缘体逐层成核所需的单层化学，这将实现更低功耗的计算或更高效的高功率通信。该项目包括旨在招募和支持对材料科学与工程或材料化学感兴趣的少数民族博士生和本科生的活动。

Technical Description: Atomic layer deposition is a cyclic chemical process that provides sub-nanometer control of layer thickness. The bonding of the first layer is the critical step in providing a low defect interface, which enables nucleation of atomic layer deposition within each unit cell. The project is developing an atomic layer understanding of oxide monolayers deposited on two very different semiconducting materials, gallium nitride and graphene, by combining scanning tunneling microscopy and scanning tunneling spectroscopy. These materials have surfaces with very low chemical reactivity, enabling the fabrication of unique electronics devices; however, these materials lack reactive atoms that can strongly bond to atomic layer deposition precursors. For graphene, the non-reactive surface is functionalized via adsorption of an ordered monolayer of organic coordination complexes while for gallium nitride and order layer of inorganic function groups are deposited. Two techniques are developed with broad applicability: (a) ultra high vacuum cross-sectional Kelvin Probe Force Microscopy to image the electrostatic potentials inside working capacitors and field effect transistors on the nanoscale and (b) contactless ultra high vacuum variable frequency capacitance-voltage for in-situ measurement of gate oxide defects.Non-technical Description: At present, computer chip speed and performance are limited by the dissipation of heat. Further increases in performance require decreasing in the supply voltage to stabilize heat dissipation per unit area. This research project seeks to develop the monolayer chemistry required for nucleating layer by layer growth of the nanoscale insulators, which will enable lower-power computing or more efficient high power communication. The project includes activities designed to recruit and support under-represented minority PhD students and undergraduate students who are interested in materials science and engineering or materials chemistry.