The phase transformations of Si under nanogrinding have been studied by transmission electron microscopy and Raman spectroscopy. Nanocrystalline high-pressure phases (Si-III/Si-XII) were found in the amorphous layer of the subsurface of heavily ground Si. The sequence of the phase transformation in nanogrinding has been found to be different to that in nanoindentation. The formation mechanism of the nanocrystalline high-pressure phases in nanogrinding is proposed based on experimental results.

Metallic W whiskers with tip diameters of 50-250 nm and lengths of 2-4 µm have been successfully synthesized in large quantities using Co-Ni alloyed catalysts. The relatively low growth temperature of 850 °C and the large catalyst size (over 100 nm) suggest that the growth of the W whiskers must be governed by the vapor-solid-solid mechanism. Our results show that the vapor-solid-solid model is suitable not only for the growth of nano-scaled whiskers with diameters below 100 nm, but also for submicro-scaled whiskers with diameters well above 100 nm. This technique has great potential to synthesize well controlled metallic whiskers.

Ordered and dense InAs quantum dots grown on patterned Si(100) with a thin GaAs buffer layer have been investigated by transmission electron microscopy and electron energy loss spectroscopy. {111} faceted InAs quantum dots with good crystallinity were observed on top of the underlying GaAs buffer layer. It was revealed that the GaAs buffer layer and the lateral expansion of InAs have played key roles in releasing the misfit strain between InAs and Si and suppressing the formation of lattice defects in InAs quantum dots. These results suggest a possible pathway for the strain relaxation in the formation of quantum dots.