Modi Gaurav, Meng Andrew C, Rajagopalan Srinivasan, Thiruvengadam Rangarajan, Davies Peter K, Stach Eric A, Agarwal Ritesh
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Nano Lett. 2024 May 15;24(19):5799-5807. doi: 10.1021/acs.nanolett.4c00878. Epub 2024 May 3.
Controlled growth of semiconductor nanowires with atomic precision offers the potential to tune the material properties for integration into scalable functional devices. Despite significant progress in understanding the nanowire growth mechanism, definitive control over atomic positions of its constituents, structure, and morphology via self-assembly remains challenging. Here, we demonstrate an exquisite control over synthesis of cation-ordered nanoscale superstructures in Ge-Sb-Te nanowires with the ability to deterministically vary the nanowire growth direction, crystal facets, and periodicity of cation ordering by tuning the relative precursor flux during synthesis. Furthermore, the role of anisotropy on material properties in cation-ordered nanowire superstructures is illustrated by fabricating phase-change memory (PCM) devices, which show significantly different growth direction dependent amorphization current density. This level of control in synthesizing chemically ordered nanoscale superstructures holds potential to precisely modulate fundamental material properties such as the electronic and thermal transport, which may have implications for PCM, thermoelectrics, and other nanoelectronic devices.
以原子精度控制半导体纳米线的生长为调整材料特性以集成到可扩展功能器件中提供了潜力。尽管在理解纳米线生长机制方面取得了重大进展，但通过自组装对其组成原子位置、结构和形态进行确定性控制仍然具有挑战性。在此，我们展示了对Ge-Sb-Te纳米线中阳离子有序纳米级超结构合成的精确控制，能够通过在合成过程中调整相对前驱体通量来确定性地改变纳米线的生长方向、晶面和阳离子有序的周期性。此外，通过制造相变存储器（PCM）器件说明了各向异性在阳离子有序纳米线超结构中对材料特性的作用，该器件显示出明显不同的依赖于生长方向的非晶化电流密度。在合成化学有序纳米级超结构方面的这种控制水平有可能精确调节诸如电子和热传输等基本材料特性，这可能对PCM、热电学和其他纳米电子器件产生影响。
