nl5b01603_si_001.mov (1.12 MB)
Determination of Young’s Modulus of Ultrathin Nanomaterials
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posted on 2015-08-12, 00:00 authored by Yujie Chen, Qiang Gao, Yanbo Wang, Xianghai An, Xiaozhou Liao, Yiu-Wing Mai, H. Hoe Tan, Jin Zou, Simon
P. Ringer, Chennupati JagadishDetermination 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.