Failure Mechanisms in Vertically Aligned Dense Nanowire Arrays

Abstract

Nanowires are an increasingly prevalent class of nanomaterials in composites and devices, with arrays and other complex geometries used in various applications. Little investigation has been done regarding the mechanical behavior of micron-sized nanowire structures. We conduct in situ microcompression experiments on vertically aligned dense microbundles of 300 nm diameter single-crystalline zinc oxide nanowires to gain insights into their structural failure. Experiments demonstrate that bundles containing approximately 10–130 nanowires experience two failure regimes: (1) localized noncatastrophic interfacial splitting and (2) global structural failure. Utilizing Weibull statistics and experimental results, we develop a technique for analyzing flaw distribution and use it to predict the expected range of bundle failure stress. This analysis provides guidelines for nanowire arrays’ susceptibility to failure, sensitivity to flaw size, interfacial interactions of constituents, and degree of alignment. This work develops insights to understand and predict fundamental failure mechanisms in highly aligned, dense structures.

Free-Standing Metal Halide Perovskite Nanowire Arrays with Blue-Green Heterostructures

“…For example, free-standing vertically aligned nanowires of Si, ZnO, GaAs, and InP have achieved excellent performance in various optoelectronic fields. 7 − 11 However, the growth of free-standing vertically aligned MHP nanowire arrays is difficult. Compared with the numerous studies on growth of horizontal MHP nanowire arrays, 2 , 12 − 17 there are only a few reports of vertically aligned nanowire arrays, and those mostly concern nanowires physically confined inside various templates such as anodized aluminum oxide (AAO).…”

“…Metal halide perovskite (MHP) nanowire arrays have shown excellent performance in optoelectronic applications such as lasers, LEDs, solar cells, and photodetection. − Vertically aligned nanowire arrays offer several advantageous properties, such as enhanced optical absorption and emission along the direction orthogonal to the substrate, which is essential for solar cells and light-emitting diodes, − as well as technical advantages including higher nanowire density and scalable device processing. For example, free-standing vertically aligned nanowires of Si, ZnO, GaAs, and InP have achieved excellent performance in various optoelectronic fields. − However, the growth of free-standing vertically aligned MHP nanowire arrays is difficult. Compared with the numerous studies on growth of horizontal MHP nanowire arrays, ,− there are only a few reports of vertically aligned nanowire arrays, and those mostly concern nanowires physically confined inside various templates such as anodized aluminum oxide (AAO). − A few studies have reported free-standing MHP nanowires by solution extrusion and vapor–liquid–solid methods, but the alignment of the obtained NWs was not satisfactory.…”