Determination of Young鈥檚 Modulus of Ultrathin Nanomaterials

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• 作者：Yujie Chen ; Qiang Gao ; Yanbo Wang ; Xianghai An ; Xiaozhou Liao ; Yiu-Wing Mai ; H. Hoe Tan ; Jin Zou ; Simon P. Ringer ; Chennupati Jagadish
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：August 12, 2015
• 年：2015
• 卷：15
• 期：8
• 页码：5279-5283
• 全文大小：362K
• ISSN：1530-6992

文摘

Determination of the elastic modulus of nanostructures with sizes at several nm range is a challenge. In this study, we designed an experiment to measure the elastic modulus of amorphous Al₂O₃ films with thicknesses varying between 2 and 25 nm. The amorphous Al₂O₃ was in the form of a shell, wrapped around GaAs nanowires, thereby forming an effective core/shell structure. The GaAs core comprised a single crystal structure with a diameter of 100 nm. Combined in situ compression transmission electron microscopy and finite element analysis were used to evaluate the elastic modulus of the overall core/shell nanowires. A core/shell model was applied to deconvolute the elastic modulus of the Al₂O₃ shell from the core. The results indicate that the elastic modulus of amorphous Al₂O₃ increases significantly when the thickness of the layer is smaller than 5 nm. This novel nanoscale material can be attributed to the reconstruction of the bonding at the surface of the material, coupled with the increase of the surface-to-volume ratio with nanoscale dimensions. Moreover, the experimental technique and analysis methods presented in this study may be extended to measure the elastic modulus of other materials with dimensions of just several nanometers.