Axial Heterostructures with Phase-Controlled Metastable Segments via Post-Growth Reactions of Ge Nanowires
Axial Heterostructures with Phase-Controlled Metastable Segments via Post-Growth Reactions of Ge Nanowires
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DOI：
10.1021/acs.chemmater.9b03000
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发表时间：
2019-09
影响因子：
8.6
通讯作者：
E. Sutter;P. Sutter
中科院分区：
文献类型：
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作者：
E. Sutter;P. Sutter
亚稳晶体相通过提供超越化学稳定的结晶固体的材料性质的访问而承诺新的功能。虽然在本体中实现亚稳相需要非平衡过程，如快速淬火或高压，但纳米尺度的尺寸效应可以促进它们在温和加工过程中的形成和稳定。在这里，我们展示了通过生长后处理的交替稳定的半导体（Ge）和亚稳金属（AuGe）段的轴向异质结构的控制形成，通过用Au装饰Ge纳米线，将它们封装在石墨碳壳中，在中等温度下退火以诱导Au和Ge在熔体中的合金化，然后缓慢冷却和结晶。该过程被扩展到形成异质结构的二元AgGe和三元AuAgGe合金段的Ge纳米线。金属合金采用通过纳米线直径选择的不同亚稳晶相。这一阶段的选择，…
Metastable crystal phases promise new functionalities by providing access to material properties beyond those of thermodynamically stable crystalline solids. While realizing metastable phases in the bulk requires nonequilibrium processes such as rapid quenching or high pressures, size effects at the nanometer scale can promote their formation and stabilization during mild processing. Here, we demonstrate the controlled formation of axial heterostructures of alternating stable semiconductor (Ge) and metastable metallic (AuGe) segments via post-growth processing by decorating Ge nanowires with Au, encapsulating them in graphitic carbon shells, annealing at moderate temperatures to induce alloying of Au and Ge in the melt, followed by slow cooling and crystallization. The process is extended to form heterostructures of binary AgGe and ternary AuAgGe alloy segments in Ge nanowires. The metallic alloys adopt different metastable crystal phases that are selected via the nanowire diameter. This phase selection, ...