Synthesis and Characterization of Thin Film Insulators: Application to Inelastic Electron Tunneling Spectroscopy

女性研究启动奖研究机会项目是在分析和表面化学的一般领域以及薄膜沉积和非弹性隧道光谱（IETS）的子领域。通常使用的衬底材料的反应性及其分解或减少吸附质种类的倾向限制了IETS技术。首席研究员将通过离子束沉积合成具有不同反应性和电子转移特性的广谱新型绝缘薄膜衬底，适用于IETS应用。薄膜材料将包括金属氧化物、金属氮化物、混合金属氧化物和类金刚石碳。薄膜的结构表征将通过电子探针分析，透射电子显微镜，红外光谱和IETS进行。将测量一些吸附探针分子的隧穿光谱，以便根据其屏障质量和化学惰性对衬底材料进行分类。利用光子作为探针的电子和振动光谱对我们了解材料的结构、键合和反应性做出了巨大贡献。然而，它们受到控制光子发射、吸收和散射的选择规则的限制。非弹性电子隧穿不受这些光学选择规则的限制，因此是吸附分子物种光谱表征的有力工具。低洼电子跃迁以及允许和禁止的振动模式都可以检测到。开发具有足够多样性的绝缘材料目录，几乎任何分子种类都可以与相对惰性的衬底相匹配，以进行光谱研究，这将大大提高该技术的普遍实用性。它将在基础分子光谱学和技术相关领域（如腐蚀、粘附、催化和微电子器件制造）中得到越来越多的应用。

This Research Opportunities for Women Research Initiation Award project is in the general area of Analytical and Surface Chemistry and in the subfields of thin film deposition and inelastic tunneling spectroscopy (IETS). The IETS technique has been limited by the reactivity of the substrate materials commonly used and their tendency to decompose or reduce the adsorbate species. The Principal Investigator will synthesize, by ion-beam deposition, a broad spectrum of new insulating thin-film substrates with varying reactivity and electron-transfer properties suitable for application with IETS. The film materials will include metal oxides, metal nitrides, mixed metal oxides, and diamond-like carbon. Structural characterization of the films will be performed by electron microprobe analysis, transmission electron microscopy, infrared spectroscopy and IETS. Tunneling spectra of a number of adsorbed probe molecules will be measured in order to classify the substrate materials with respect to their barrier quality and chemical inertness. Electronic and vibrational spectroscopies utilizing photons as probes have contributed greatly to our knowledge of the structure, bonding and reactivity of materials. They are limited, however, by the selection rules that govern photon emission, absorption and scattering. Inelastic electron tunneling is not limited by these optical selection rules and is thus a powerful tool for spectroscopic characterization of adsorbed molecular species. Low-lying electronic transitions and both allowed and forbidden vibrational modes can be detected. Development of a catalog of insulating materials with sufficient diversity that virtually any molecular species can be matched to a relatively inert substrate for spectroscopic investigation will greatly enhance the general utility of this technique. It will find increased application both in fundamental molecular spectroscopy and in technologically relevant fields such as corrosion, adhesion, catalysis and microelectronic device fabrication.