Real-time imaging of light-induced transformations in phase-change materials

相变材料中光诱导转变的实时成像

• 批准号: RGPIN-2021-03797
• 负责人: Beyerlein, Kenneth
• 金额: $ 2.11万
• 依托单位: Institut national de la recherche scientifique
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742720
• 关键词: Real; time; imaging; light; induced

In this digital age, we rely on computers in many aspects of our daily life. Their performance not only influences how we communicate and work, but also the efficacy of our banks and medical care. It is then in the best interest of Canada to invest in their development to maintain a strategic advantage in this sector. This Discovery Grant (DG) contributes to this goal by studying the dynamics of phase-change materials that are important for computer memory devices and have the potential to enable more efficient computer architectures. Today's computers follow a von Neumann architecture, where data must be moved between physically separate processing and memory units. As the speed of processors has outpaced that of memory, the bottle neck is now the time it takes to shuttle data back and forth. This can be overcome by performing both actions in a single device, referred to as in-memory computing. However, practical realization of such devices requires materials that can both rapidly and irreversibly switch between states for combined fast processing and non-volatile memory functionality. Phase-change materials based on chalcogenide alloys have been largely investigated for this purpose, and are already used in the computer industry for optical data storage - the composition Ge2Sb2Te5 is used in DVDs, and Ge8Sb2Te11 is used in Blue-ray disks. Data can be written in these devices using a laser or electric current to locally heat a small region, and switch it between an insulating amorphous glass phase and a conductive crystalline phase. The resultant phase is determined by the amount of heat absorbed in the process that is controlled by the incident laser power or electric current. However, the maximum data writing speed is currently limited by the amorphous to crystalline phase transformation time. It is then the goal of this DG to explore ways to increase this transformation speed and track the corresponding material structural evolution in real time using the dynamic transmission electron microscope (DTEM) at INRS. This unique microscope has the capability to capture a sequence of nanosecond images of irreversible transformations with near-atomic resolution. Specifically, this DG will address critical outstanding questions about the crystallization of phase-change materials by exploring the following research directives: (1) imaging rapidly cooled transformations, (2) tracking precursors in the amorphous phase, and (3) ultra-localized nano-plasmonic heating. This research is expected to lead to a deeper understanding of this technologically important transformation, which can impact the future design of computers. Furthermore, the expertise gained by highly qualified personnel trained in this program is widely transferable to other sectors of the Canadian technology industry.

在这个数字时代，我们日常生活的许多方面都依赖于计算机。他们的表现不仅影响我们的沟通和工作方式，还影响我们银行和医疗保健的效率。因此，投资于它们的发展，以保持在这一部门的战略优势，符合加拿大的最佳利益。这项发现奖助金(DG)通过研究相变材料的动力学为这一目标做出了贡献，相变材料对计算机存储设备非常重要，并有可能实现更高效的计算机体系结构。今天的计算机遵循冯·诺伊曼体系结构，数据必须在物理上独立的处理单元和存储单元之间移动。由于处理器的速度已经超过了内存的速度，现在的瓶颈是来回传输数据所需的时间。这可以通过在单个设备中执行这两个操作来克服，称为内存计算。然而，这种器件的实际实现需要能够快速且不可逆地在状态之间切换的材料，以结合快速处理和非易失性存储器功能。基于硫系合金的相变材料已经为此目的进行了大量研究，并已在计算机工业中用于光学数据存储-组成Ge2Sb2Te5用于DVD，Ge8Sb2Te11用于蓝光光盘。可以使用激光或电流在这些设备中写入数据，以局部加热一小块区域，并在绝缘非晶态玻璃相和导电晶相之间切换。合成的相由入射激光功率或电流控制的过程中吸收的热量决定。然而，目前最大的数据写入速度受到非晶态到晶态相变时间的限制。因此，本DG的目标是探索提高这种转变速度的方法，并使用INRS的动态透射电子显微镜(DTEM)实时跟踪相应的材料结构演变。这种独特的显微镜能够以近原子的分辨率捕捉一系列不可逆转变的纳秒图像。具体地说，本DG将通过探索以下研究方向来解决关于相变材料晶化的关键悬而未决的问题：(1)快速冷却相变的成像，(2)跟踪非晶相中的前体，以及(3)超局域纳米等离子体加热。这项研究有望加深对这一具有重要技术意义的转变的理解，这一转变可能会影响未来的计算机设计。此外，通过该计划培训的高素质人员所获得的专业知识可以广泛地转移到加拿大技术行业的其他部门。