Materials World Network: Understanding and exploiting mixed, ultra-fast optical electrical behavior in nanoscale phase change materials

这项建议的目的是全面研究在混合光电相变中Chacgenide(包括二元和三元化合物)的材料性质。Ge-Sb-Te合金记忆存储的基本原理是可逆的晶态到非晶态的相变，这种相变与光学反射率和电阻率的显著变化有关。然而，尽管已经独立地研究了光学和电学机制，但还没有关于混合模式操作的工作，即在对材料进行光学切换的同时对其进行电探测，反之亦然。然而，这对于从光学选通超快晶体管到非冯-诺伊曼算术处理等一系列潜在的改变游戏规则的应用来说是极其重要的。我们的合作研究将集中在研究混合模式下的基本相变性质，通过动态光学探测电相变来阐明相变机制，并探索最适合于未来非传统算术处理器的材料。为了实现这些具有挑战性的目标，将采取以下方法：1.发展脉冲激光沉积(PLD)生长技术，以合成化学成分和直径可控的复杂的三元相变纳米线；然后对其结构、化学和电学特性进行表征。通过混合模式时间分辨飞秒光学和超快电学测量研究相变动力学行为，以及这种行为与相变纳米线的化学成分和尺寸的依赖关系。通过专用纳米光子学实验台详细研究相变材料中混合模操作的尺寸依赖性

The objective of this proposal is to comprehensively investigate the material properties of chacogenides (both binary and ternary compounds) in mixed optical-electrical phase transitions. The underlying principle of memory storage in Ge-Sb-Te alloys is reversible crystalline to amorphous phase transitions that are associated with significant changes in optical reflectivity and electrical resistivity. However, although the optical and electrical mechanisms have been independently investigated, there is no work done on the mixed-mode operation, i.e. switching the material optically while probing it electrically and vice-versa. This is however extremely important for a host of potentially game-changing applications ranging from optically gated ultra-fast transistors to non-von-Neumann arithmetic processing. Our collaborative research will focus on investigating fundamental phase switching properties in mixed-mode, elucidating phase change mechanisms via dynamic optical probing of electrical phase transitions, and exploring the materials best suited for unconventional future arithmetic processors. To accomplish these challenging objectives, the following approach will be undertaken:1. The development of pulsed laser deposition (PLD) growth technique to synthesize complex ternary phase change nanowires with excellent control over chemical composition and diameters; followed by their structural, chemical and electrical characterization.2. The study phase-change dynamics by mixed-mode time-resolved femtosecond optical and ultrafast electrical measurements of phase switching behavior, and the dependence of such behavior on the chemical composition and size of the phase-change nanowires.3. A detailed study of the size-dependency of mixed-mode operation in phase change materials via a dedicated nano-photonics test bed