Papers by Author: Jin Zou

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Authors: Y.Q. Wu, Han Huang, Jin Zou
Abstract: In this work, deformation of monocrystalline silicon (Si) under nanoscratching was investigated using transmission electron microscopy (TEM). The results indicated that no fracture occurred during nanoscratching with loads ranging from 1 to 6 mN. The damaged regions induced by nanoscratching included an amorphous Si region and a damaged crystalline Si region. Detailed TEM analyses revealed that at the lowest load of 1 mN no dislocation was observed in the damaged crystalline region, and only stacking faults were observed at the boundary between the damaged crystalline Si and amorphous Si. Dislocations started to nucleate along (111) planes and penetrated into the bulk Si when the normal load was increased to 2 mN and above. Defects perpendicular to the scratched surface were initiated when the load was greater than 4 mN. The density of dislocations also increased rapidly with the increase of the applied load.
Authors: Xue Gang Tang, Meng Hou, Jin Zou, Rowan Truss
Abstract: A nano-filler network constructed by layered silicates and multi-wall carbon nanotubes (MWCNTs) has been prepared. The structure of the network was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), transmission electron microscopy (TEM), and dynamic rheological test. The results showed that a plateau in the storage modulus at low frequency occurred, which indicated the pseudo solid-like behaviour for the sample with nano-filler network, and the jamming effect due to the nano-filler network dominated the viscoelatic behaviour at low frequency. This effect was sensitive to the frequency and decreased quickly with the increase of frequency. At the same time, the introduction of nanofillers and the presence of nano-filler network affected the complex viscosity and shear thinning too, especially at low frequency.
Authors: Meng Hou, Xue Gang Tang, Jin Zou, Rowan Truss
Abstract: Polyvinylidene fluoride (PVDF)/Carbon nanotubes (CNTs) and PVDF/Organo-modified layered silicates (OMLSs) nano-composites were prepared by phase inversion technique. Maleic anhydride grafted PVDF (PVDF-MAH), were used to fine tune the interface. Transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used to characterize the nanocomposites. Elastic modulus and creep resistance of the PVDF nanocomposites were evaluated according to ASTM D-638. The results showed that both CNTs and OMLSs were good candidates to reinforce the PVDF and the addition of PVDF-MAH enhanced the interface between nanoparticles and PVDF, leading to further increase of mechanical property.
Authors: Sima Dimitrijev, Ji Sheng Han, Jin Zou
Abstract: High-resolution transmission electron microscopy (HR TEM) reveals an atomically flat SiC surface after oxidation in either NO or dry O2 ambients. This reopens the question of the origin of the electronically active defects at the SiO2–SiC interface, whose density remains orders of magnitude higher than in the SiO2–Si interface. Capacitance-transient measurements, analysed in this paper, demonstrate that the dominant electronically active defects are in the oxide at tunneling distances from the SiC surface (near-interface traps). The HR TEM results cannot rule out that these traps are related to carbon/oxygen bonds or even nanometer-sized carbon clusters, which resolves the apparent inconsistency with the earlier experimental evidence of carbon accumulation at (or near) the SiO2–SiC interface.
Authors: B.L. Wang, Han Huang, Jin Zou, Li Bo Zhou
Abstract: Silicon (100) substrates machined by chemo-mechanical-grinding (CMG) and chemicalmechanical- polishing (CMP) were investigated using atomic force microscopy, cross-sectional transmission electron microscopy and nanoindentation. It was found that the substrate surface after CMG was slightly better than machined by CMP in terms of roughness. The transmission electron microscopy analysis showed that the CMG-generated subsurface was defect-free, but the CMP specimen had a crystalline layer of about 4 nm in thickness on the top of the silicon lattice as evidenced by the extra diffraction spots. Nanoindentation results indicated that there exists a slight difference in mechanical properties between the CMG and CMP machined substrates.
Authors: Xue Gang Tang, Meng Hou, Jin Zou, Rowan Truss
Abstract: Poly(vinylidene fluoride)/Microcrystalline cellulose (MCC) nanocomposites were prepared by ultrasonic treatment and magnetic stir. Poly(vinylidene fluoride)-graft-maleic anhydride (PVDF-g-MAH) was added to promote matrix–filler compatibility. Transmission electron microscopy (TEM) results showed that the diameter of the MCC was decreased to several tens nanometers by the treatment of ultrasonic and magnetic stir. The results of differential scanning calorimetry (DSC) showed that the peak crystallisation temperatures (Tc) and the crystallisation enthalpy ΔHc increased with the addition of MCC, and the melting enthalpy ΔHm increased. With the addition of the compatibilizer (PVDF-g-MAH), peak crystallisation temperatures increased further, while without further increase of the ΔHc. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) showed that the addition of MCC induced β-phase PVDF, and the addition of PVDF-g-MAH can induce more β-phase PVDF. Mechanical properties of the nanocomposites were evaluated and the results showed that the addition of MCC did not increase the Young’s modulus, while the tensile strength and elongation at break decreased.
Authors: Han Huang, Y.Q. Wu, Y. Wang, Jin Zou, Li Bo Zhou
Abstract: This paper reports the effect of nanogrinding conditions on the formation of subsurface structures of monocrystalline silicon (100) substrates. It was found that the amorphization and the transformation of high pressure phases were related to the grit depth of cut employed in nanogrinding. The formation mechanisms were found to be different from those previously reported from the nanoindentation studies.
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