Crystalline core/shell Si/SiO2 nanotubes formed via interfacial stress imbalance.
Crystalline core/shell Si/SiO2 nanotubes (NTs) with outer diameters of 130-220 nm and lengths of approximately 1 microm have been synthesized using thermal evaporation. High resolution scanning electron microscopy reveals that the NT formation stems from the intrinsic interfacial stress imbalance in the strained Si/SiO2 bilayered film, consequently leading to NTs with different orifice levels. The NT diameters depend strongly on the bilayer film thicknesses and crystal orientations of the Si and SiO2 layers. A modified Timoshenko formula is derived to calculate the dependence of the tube diameter on the bilayer film thickness. The obtained results are consistent well with experimental data.
Nanjing National Laboratory of Microstructures and Department of Physics, Nanjing University, Nanjing 210093, PR China.
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LZ
Liu
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Wu
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ZY
Zhang
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Xu
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Li
Paul K
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Chu