Science of Electron-conducting Filaments in Ion-conducting Chalcogenide Glasses

离子导电硫族化物玻璃中电子导电丝的科学

• 批准号: 1507670
• 负责人: Gang Chen
• 金额: $ 49.9万
• 依托单位: Ohio University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1507670&HistoricalAwards=false
• 关键词: Science; Electron; conducting; Filaments; Ion

NON-TECHNICAL DESCRIPTION: This proposal aims to address a fundamental question of charge and mass transport in ion-conducting glasses: how does an electric field create an electron-conducting path in metal-doped glasses (that contain S, Se or Te)? Under a strong external electric field, an electron-conducting path is created or annihilated inside the solid electrolyte depending on the direction of the electric field. The observed reversible creation/annihilation of electron-conducting paths by external fields mimics 0 and 1 states of a binary system and is the basis underlying conductive bridging random access memory (CBRAM), a novel non-volatile memory technology based upon bipolar resistive switching. The goal of this project is to understand the destruction and formation mechanism of the conductive filaments through integrated experiment/theory approaches. Success of this project provides fundamental understanding of the emerging CBRAM technology and promises transformation of electronically insulating glasses to electronically conducting glasses. The impact of this research is broadened further by engaging students typically underrepresented in science and engineering to participate in the research project. Summer internships are offered to undergraduate students through the on-campus Research Experience for Undergraduates program. Outreach to children with autism spectra disorder in Appalachian Ohio is offered through science demonstrations, workshops and summer camp activities.TECHNICAL DETAILS: Fast-ion conductors based upon solid electrolyte glasses have many advantages over their crystalline counterparts. For example, Ag doped chalcogenide glasses exhibit extremely high ionic conductivity. An interesting twist for these materials is that under a strong external electric field, an electron-conducting path is created inside the solid electrolyte. It is widely speculated that formation of metal filaments through field-driven electrochemical reactions is responsible for the enhanced electronic conductivity. However, this view leads to an erroneous prediction that superfast motion of both the metal ions and the solid electrolyte host occurs simultaneously under the external field. A hypothesis of this grant is that the electron-conducting filaments created by the external electric field are not made simply of metal, but complex semiconducting compounds that involve concentrated ions trapped by the ion-trap centers in the solid electrolytes. Prototypical metal-doped chalcogenide glasses (i.e., Ag and Cu doped Ge-Se and Sb-Te) were selected for study. Advanced experimental and theoretical techniques are applied to understand the charge and mass transport in the solid electrolytes under external fields. A novel simulation technique called experimentally constrained molecular relaxation (ECMR) is used to ensure maximal coincidence between theory and experiment. Structure, properties and dynamics of the electron-conducting filaments generated by the electric field are studied through the integrated experiment/theory approach. This project provides atomistic insight into the dynamics of filament formation and structure-property relations of the electron-conducting filaments. Undergraduate and graduate students participating in this project are trained on cutting-edge research facilities such as those in Advanced Photon Source and Center for Nanoscale Materials at Argonne National Lab and the Ohio Supercomputing Center. Outreach to children with autism spectral order is offered to enhance their interest in college education and careers in information technology.

非技术描述：该提案旨在解决离子传导玻璃中电荷和质量传输的基本问题：电场如何在金属掺杂玻璃（含有 S、Se 或 Te）中创建电子传导路径？在强的外部电场下，根据电场的方向，在固体电解质内部创建或消除电子传导路径。观察到的外部场对电子传导路径的可逆创建/湮灭模拟了二元系统的 0 和 1 状态，并且是传导桥接随机存取存储器 (CBRAM) 的基础，CBRAM 是一种基于双极电阻开关的新型非易失性存储器技术。该项目的目标是通过综合实验/理论方法了解导电丝的破坏和形成机制。该项目的成功提供了对新兴 CBRAM 技术的基本了解，并有望将电子绝缘玻璃转变为电子导电玻璃。通过让科学和工程领域代表性不足的学生参与研究项目，这项研究的影响进一步扩大。通过本科生校园研究体验项目为本科生提供暑期实习机会。通过科学演示、研讨会和夏令营活动，为阿巴拉契亚俄亥俄州患有自闭症谱系障碍的儿童提供服务。技术细节：基于固体电解质玻璃的快离子导体比晶体同类导体具有许多优势。例如，掺银硫族化物玻璃表现出极高的离子电导率。这些材料的一个有趣的变化是，在强外部电场下，固体电解质内部会产生电子传导路径。人们普遍推测，通过场驱动的电化学反应形成金属丝是电子电导率增强的原因。然而，这种观点导致错误的预测，即金属离子和固体电解质主体在外场下同时发生超快运动。这项资助的一个假设是，由外部电场产生的电子传导丝不是简单地由金属制成，而是复杂的半导体化合物，其中包含被固体电解质中的离子捕获中心捕获的浓缩离子。选择典型的金属掺杂硫系玻璃（即Ag和Cu掺杂的Ge-Se和Sb-Te）进行研究。应用先进的实验和理论技术来了解外部场下固体电解质的电荷和质量传输。使用一种称为实验约束分子弛豫 (ECMR) 的新颖模拟技术来确保理论与实验之间的最大一致性。通过综合实验/理论方法研究了电场产生的电子传导丝的结构、性质和动力学。该项目提供了对细丝形成动力学和电子传导细丝的结构-性能关系的原子学见解。参与该项目的本科生和研究生接受了尖端研究设施的培训，例如阿贡国家实验室的先进光子源和纳米材料中心以及俄亥俄州超级计算中心的设施。对患有自闭症谱序的儿童进行外展活动，以提高他们对大学教育和信息技术职业的兴趣。