Nanometallicity in Si-based Amorphous Thin Films

摘要技术：这个项目的目的是发现新的随机材料，当样品大小与电子的局域长度相当时，这些材料表现出金属-绝缘体的转变。最近在钙钛矿固溶体和与铂原子分散的二氧化硅中观察到的这种材料，可能会在非易失性存储器中找到潜在的电阻开关应用。这些材料是绝缘体和金属部件的固体溶液。通过改变薄膜的成分和厚度，我们将设计一种可调的安德森类型的金属-绝缘体转变，绝缘厚度较大，但金属厚度较小。由于电荷注入/移除而产生的电压也可以触发该转变，这改变了局域化长度。局部原子结构和金属丰度将使用同步辐射、电子能量损失光谱和光学光谱学来确定，而远程金属丰度和跃迁将使用输运/介电测量和原子模拟来确定。围绕博士教育、实验室经验和远程实验室访问建立的综合研究和教育活动将使本地和远程的本科生和研究生以及高中和大学教师受益。非技术性：该项目探索纳米级的基础材料研究，其中量子物理的预测可以直接应用于材料设计，具有潜在的高回报。这项研究的动机是对用于计算机，特别是手持数字设备的占地面积更小、速度更快的新存储材料的需求永无止境。与专注于不断完善和纯度不断提高的材料(如硅单晶)的传统方法不同，该项目转向杂质浓度较高的随机材料。如果该项目成功，它将开辟一条新的技术机会之路。教育计划与研究相结合：它强调将教学学习和实验室学习结合起来，面向本地和远程本科生和研究生，他们将通过在线访问获得实验室经验。

AbstractTechnical: This project aims for the discovery of new random materials that exhibit metal-insulator transitions when the sample size is comparable to electron's localization length. Such materials, recently observed in perovskite solid solutions and in SiO2 atomically dispersed with Pt, may find potential applications for resistance switching in non-volatile memory. These materials are solid solutions of an insulator and a metallic component. By varying the composition and the thickness of the thin films, we will engineer a tunable metal-insulator transition of the Anderson variety, being insulating at larger thickness, but metallic at smaller thickness. The transition can also be triggered by a voltage due to charge injection/removal, which alters the localization length. Local atomic structures and metallicity will be determined using synchrotron radiation, electron energy loss spectroscopy, and optical spectroscopy, whereas long range metallicity and transitions will be established using transport/dielectric measurements and atomistic simulations. Integrated research and educational activity built around PhD education, laboratory experience and remote laboratory access will benefit local and distant undergraduate and graduate students, as well as high school and university teachers.Nontechnical: The project explores fundamental material research at the nanoscale level where the prediction of quantum physics can be directly applied to material design with a potentially high payoff. The research is motivated by the insatiable need for new memory materials with a smaller footprint and a faster speed, to be used in computers and especially hand-held digital devices. Unlike conventional approaches that focus on materials of ever increasing perfection and purity, such as silicon single crystal, this project turns to random materials with a high concentration of impurities. If the project is successful, it will open a new avenue of technological opportunities. An education plan is integrated with the research: it emphasizes integration of instruction learning and laboratory learning, for both local and distant undergraduate and graduate students who, via on-line access, will gain laboratory experience.