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High-quality GaP, GaP@GaN and GaN@GaP nanowires were grown by a convenient vapor deposition technique. The wire-like and two-layers structures of GaP@GaN and GaN@GaP core-shell nanowires were clearly resolved using X-ray powder diffraction and high-resolution transmission electron microscopy (HRTEM) and their growth directions were identified. Photoluminescence intensity of GaP@GaN nanowires increased as temperature increased. The result was interpreted by the piezoelectric effect induced from lattice mismatch between two semiconductor layers. An unexpected peak at 386 cm-1 was found in the Raman spectra of GaN@GaP and assigned to a surface phonon mode due to the interface. Detailed synthetic conditions and possible growth mechanisms of those nanowires were proposed.

Isothermal crystallization kinetics of Ni24Zr76 amorphous alloy has been studied by differential scanning calorimetry (DSC). Theoretically estimated transient times are found to be consistent with the experimentally observed incubation periods. The crystallization kinetics has been analyzed in terms of Kolmogorov-Johnson-Mehl-Avrami (KJMA) Model and significant departure from the linear KJMA behavior was observed. Such non-linearity is due to the surface-induced crystallization, anisotropie growth of the crystals, impingement effects and variation of the nucleation rate during crystallization etc. By applying high-resolution electron Microscopy (HREM), it has been shown that the nucleation and growth of the crystals do not take place at a constant state of disorder.

High resolution transmission electron microscopy (HRTEM) has been applied to study the atomic structure of NiSi2 /(001)Si interface. Previous HRTEM result suggested that Ni atoms in the boundary core are six-fold coordinated and Si atoms are everywhere tetrahedrally coordinated. In this work, high resolution imaging technique and computer image simulation were used to study the atomic structure of NiSi2 /(001)Si interfaces and a new interface structure was found. For the new interface structure, Ni and Si atoms are also six-fold and tetrahedrally coordinated, respectively, with an extra layer of fourfold planar bonded Si atoms present at the interface.

High resolution imaging technique is applied to systematically study the Σ =3 NiSi2 $$(\overline{1}11)/(1\overline{1}5)$$ Si and NiSi2 $$(2\overline{2}1)$$ /(001)Si interfaces. The long-period boundaries of Σ =3 NiSi2 $$(\overline{1}11)/(1\overline{1}5)$$ Si and NiSi2( $$(2\overline{2}1)$$ /(001)Si have been shown to decompose into short period of symmetrical NiSi2 $$(\overline{1}1\overline{1})/(\overline{1}11)$$ Si and NiSi2 $$(\overline{1}12)/(1\overline{1}2)$$ Si atomic facets which are similar to the case of asymmetrical twin boundaries in NiSi2 crystal. This result is consistent with the computer simulation in grain boundary case that asymmetrical tilt boundaries which are generally of longer periods may facet on an atomic scale into short period symmetrical boundaries. The domain-related atomic faceting interfaces have been found in both of Σ =3 NiSi2 $$(\overline{1}11)/(1\overline{1}5)$$ Si and NiSi2 $$(2\overline{2}1)$$ /(001)Si interfaces. The coexistence of two domain-related atomic faceting interfaces in the Σ =3 NiSi2 $$(\overline{1}11)/(1\overline{1}5)$$ Si has also been observed in different area of an interface which are separated by a 1/4 type of dislocation associated with a ‘demi-step’. The Burgers vector and step of a dislocation required to separate two domain structures in the Σ =3 NiSi2/Si interface can be derived from the CCSL model.

High resolution and conventional transmission electron microscopy have been applied to study the interfacial reaction of yttrium thin films on Si. Epitaxial Ysi2−x film was grown on (111)Si by rapid thermal annealing at 500–1000 °C. The orientation relationship between yttrium silicide and (111)Si was determined to be [0001]Ysi2−x//[111]Si and (1010)Ysi2−x//(112)Si. The vacancies in the Ysi2−x film were found to be ordered in the Si sublattice plane and form an out-of-step structure. The range of M values of the out-of-step structure was found to narrow with annealing temperature and time. Defects along specific crystallographic directions were observed and analyzed to be intrinsic stacking faults.

As an “archtypal” spin-glass system, the local atomic arrangement in Au-Fe alloys is still a controversial subject. In the present experiment, Au-Fe alloys with Fe content from 10.7 to 33% were studied as to microstructure evolution, through various transmission electron microscopic techniques. Information derived from aging experiments using real and reciprocal spaces appears to suggest the coexistence of short-range-order and Fe-clusters. At early stages of aging, lobe-like and/or rod-shaped strain contrast images, identified as clusters, were revealed after specimens were further cleaned by an ion-miller. The (1 1/2 0) special point diffuse reflections were prominent in the as-quenched condition and/or early stage aging, and the intensifies decrease gradually as aging proceeds. After a certain period, (1 1/2 0) diffuse reflections disappear but strain contrast images still remain similar. This suggests that the strain contrast images are not related to the (1 1/2 0) diffuse reflections. High resolution electron microscopy was also employed. The results are consistent with the arguments derived from aging experiments.

The morphology and crystal structure of diamond crystallites grown by radio frequency (RF) and microwave (MW) plasma enhanced chemical vapor deposition (PECVD) under comparable conditions are examined by electron microscopy and found to be a strong function of the plasma. A novel TEM sample preparation method is developed to examine the internal structure of diamond as well as interfacial structure between diamond and substrate by direct deposition of diamond crystallites on prethinned metal grids. The diamond crystallites grown by RF PECVD are highly defective and composed of nanocrystalline grains of random orientation while those grown by MW PECVD are wellfaceted and process near perfect long range order in crystal structure.