Cubic boron nitride (c-BN) nanocrystals have been synthesized by pulsed laser induced liquid-solid interfacial reaction. It is shown that the diameters of the prepared quasi-spherical c-BN nanocrystals vary from 30 to 80 nm via transmission electron microscopy (TEM). The 2θ values of the X-ray diffraction (XRD) peaks of the resultant c-BN nanocrystals are 43.16°, 74.16°, 90.08° and 136.1°, respectively, corresponding to the (111), (220), (311) and (331) crystalline planes of a c-BN phase. Fourier transform infrared (FTIR) spectroscopy has also been used to characterize the structure of boron nitride. The formation of c-BN nanocrystals upon pulsed laser ablation a the liquid-solid interfaceis discussed in detail.

Based on the carbon thermodynamic equilibrium phase diagram, a nanoscaled thermodynamic approach, taking the effect of nanosize-induced additional pressure on Gibbs free energy of diamond critical nuclei and phase transition probability from graphite to diamond into account, was performed to elucidate diamond nucleation on nondiamond surfaces upon chemical vapor deposition (CVD). The theoretical analysis showed that the capillary effect of the nanosize curvature of diamond critical nuclei could drive the metastable phase region of nucleation of CVD diamond into a new stable phase region in the carbon diagram. Consequently, diamond nucleation is preferable to graphite phase formation in competing growth of diamond and graphite upon CVD

The nucleation thermodynamics of quantum dots growth in the V-groove microscopic structure on the flat substrate by vapor phase deposition was studied, and it is proposed that the quantum dots can be formed in the designed microscopic structure by controlling the nucleation. Comparing the Gibbs free energies of the critical nuclei forming in the V-groove structure and on the flat, we found that the nuclei can form in the V-groove structure prior to the flat. Based on the V-groove structure trapping adatoms effect, the growth rate of the nuclei in the V-groove structure was calculated to be much larger than that of the nuclei on the flat upon vapor phase deposition.

A microstructure of nanosized quasicrystals embedded in an amorphous matrix was formed in the Fe70Cu30 multilayered films upon room temperature 200keV xenon ion irradiation. The initial Fe and Cu crystalline phases in the as-deposited multilayers transformed into a unique amorphous phase at a dose of 831014 Xe1cm 22 and further irradiation, i.e., up to a dose of 531015 Xe1cm 22, induced the growth of the quasicrystals in some local areas in the amorphous matrix. High-resolution electron microscopy examination revealed that the compositions of the quasicrystals and amorphous matrix were close to Fe50Cu50 and Fe70Cu30, respectively. Apparently, the above microstructure was formed through a two-step phase transition along the increase of ion dose and the amorphous-to-quasicrystal transition was discussed in terms of the similarity in the atomic configuration between the icosahedral and amorphous short-range orders.

We presented the results on the fabrication and characterization of high-quality heterojunction between p-type diamond single-crystalline film and n-type cubic boron nitride (c-BN) bulk single crystal. By employing a simple surface diffusion, we prepared the n-type c-BN bulk single crystals with relatively low resistivity (1.031021 V cm). Combining p-type diamond films grown by chemical vapor deposition with n-type c-BN, we fabricated a high-quality heterojunction bipolar p-ndiode, which the turn-on voltage of the heterojunction was 0.85 V, and the current density reached to 170 A/m2 when the forward bias was applied to 3 V.