Metal oxide nanowires represent promising candidates for the fabrication of nanodevices, particularly strain sensors. However, the applications have been limited by the intrinsic brittleness of these materials. We demonstrate that this limitation can be addressed through secondary treatment by femtosecond laser irradiation. We show that the mechanical properties of CuO nanowires at room temperature can be adjusted to reduce brittle failure and enhance plasticity. The micro-mechanisms involved in induced plasticity by femtosecond laser processing are addressed using transmission electron microscopy images. At moderate laser fluence, this treatment induces plasticity in CuO nanowires by generating an enhanced density of oxygen vacancies, leading to turn the nanowires configuration from fractured to mostly bent. In bent nanowires, due to high strain rate, vacancy migration from bending tension to compression region leads to localized laser-induce phase transformation from CuO to oxygen-deficient compositions. The coalescence of femtosecond laser-induced oxygen vacancies paves the way for activation of pipe diffusion mechanism which in turn facilitates dislocation movement, leading to substructure development. Moreover, nanoindentation analyses are utilized as a further support to truly demonstrate that the femtosecond processed nanowire offers a metal-like plastic behavior. This promising result can be considered to improve the nanowire performance in future application.

中文翻译：

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飞秒激光诱导 CuO 纳米线的可塑性


金属氧化物纳米线代表了制造纳米器件，特别是应变传感器的有希望的候选者。然而，这些材料的固有脆性限制了其应用。我们证明这一限制可以通过飞秒激光照射的二次处理来解决。我们表明，可以调节 CuO 纳米线在室温下的机械性能，以减少脆性破坏并增强塑性。使用透射电子显微镜图像解决了飞秒激光加工诱导塑性所涉及的微观机制。在中等激光能量密度下，这种处理通过产生增强的氧空位密度来诱导 CuO 纳米线的可塑性，从而使纳米线结构从断裂变为大部分弯曲。在弯曲纳米线中，由于高应变率，空位从弯曲张力区域迁移到压缩区域导致局部激光诱导相变，从 CuO 到缺氧成分。飞秒激光诱导的氧空位的合并为管道扩散机制的激活铺平了道路，这反过来又促进了位错运动，导致亚结构的发展。此外，纳米压痕分析被用作进一步的支持，以真正证明飞秒加工的纳米线具有类似金属的塑性行为。这一有希望的结果可以被认为可以提高纳米线在未来应用中的性能。