Elastic Properties of GaN Nanowires: Revealing the Influence of Planar Defects on Young鈥檚 Modulus at Nanoscale

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• 作者：Sheng Dai ; Jiong Zhao ; Mo-rigen He ; Xiaoguang Wang ; Jingchun Wan ; Zhiwei Shan ; Jing Zhu
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：January 14, 2015
• 年：2015
• 卷：15
• 期：1
• 页码：8-15
• 全文大小：520K
• ISSN：1530-6992

文摘

The elastic properties of gallium nitride (GaN) nanowires with different structures were investigated by in situ electron microscopy in this work. The electric-field-induced resonance method was utilized to reveal that the single crystalline GaN nanowires, along [120] direction, had the similar Young鈥檚 modulus as the bulk value at the diameter ranging 92鈥?10 nm. Meanwhile, the elastic behavior of the obtuse-angle twin (OT) GaN nanowires was disclosed both by the in situ SEM resonance technique and in situ transmission electron microscopy tensile test for the first time. Our results showed that the average Young鈥檚 modulus of these OT nanowires was greatly decreased to about 66 GPa and indicated no size dependence at the diameter ranging 98鈥?71 nm. A quantitative explanation for this phenomenon is proposed based on the rules of mixtures in classical mechanics. It is revealed that the elastic modulus of one-dimensional nanomaterials is dependent on the relative orientations and the volume fractions of the planar defects.