Nanoscale Crystalline to Amorphous Phase Transition Studies in Nanowires: Controlled Synthesis, Characterization, Memory Switching Devices and Size-Dependent Properties

纳米线中纳米级晶体到非晶态的相变研究：受控合成、表征、存储开关器件和尺寸相关特性

• 批准号: 0706381
• 负责人: Ritesh Agarwal
• 金额: $ 35.41万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0706381&HistoricalAwards=false
• 关键词: Nanoscale; Crystalline; Amorphous; Phase; Transition

Technical: This project addresses reversible crystalline to amorphous phase transition phenomena in self assembled Ge-Sb-Te nanowire (NW) materials at sub-lithographic length scales. The approach focuses on synthesis and characterization of complex, well defined Ge-Sb-Te NWs with control over composition and dimension for investigating fundamental phase switching properties, and assembly of prototype memory elements. Components of the approach include: 1) Development of pulsed laser deposition (PLD) growth technique to synthesize complex ternary Ge-Sb-Te NWs with precise control over NW chemical composition and diameters. 2) Characterization of structural and chemical composition of NWs with electron microscopy (SEM, TEM). 3) Investigation of electric field induced phase switching behavior and its dependence on chemical composition and size (diameter) of NWs. Study of the influence of size on thermodynamic parameters and its affect on phase transition mechanism in NWs. 4) Insitu TEM analysis of structural transformations in Ge-Sb-Te NWs as a function of applied current pulses. Size and chemical composition dependent study of amorphization and recrystallization mechanism in NWs. 5) Fabrication of novel NW memory devices based on insights obtained from the experiments described above. Non-technical: The project addresses basic research issues in a topical area of electronic/photonic materials science with high technological relevance. Research and educational activities will be integrated by the involvement of undergraduates in the research program, incorporating new research results in a teaching module, and training high school and college teachers from the Philadelphia district with student population from minority and underrepresented sections.

技术：该项目解决了亚光刻长度尺度自组装 Ge-Sb-Te 纳米线 (NW) 材料中的可逆结晶到非晶相变现象。该方法侧重于复杂、明确的 Ge-Sb-Te 纳米线的合成和表征，并控制成分和尺寸，以研究基本相切换特性以及原型存储元件的组装。该方法的组成部分包括：1）开发脉冲激光沉积（PLD）生长技术来合成复杂的三元Ge-Sb-Te纳米线，并精确控制纳米线的化学成分和直径。 2）用电子显微镜（SEM，TEM）表征纳米线的结构和化学成分。 3）研究电场引起的相转换行为及其对纳米线化学成分和尺寸（直径）的依赖性。研究尺寸对热力学参数的影响及其对纳米线相变机制的影响。 4) Ge-Sb-Te NW 结构转变随施加电流脉冲变化的原位 TEM 分析。纳米线中非晶化和再结晶机制的尺寸和化学成分依赖性研究。 5) 根据从上述实验中获得的见解制造新型 NW 存储器件。非技术性：该项目解决具有高度技术相关性的电子/光子材料科学主题领域的基础研究问题。研究和教育活动将通过本科生参与研究计划、将新的研究成果纳入教学模块、以及培训费城地区的高中和大学教师以及少数族裔和代表性不足群体的学生群体来整合。