Studies of pressure induced phase transformations of ZnS nanoparticles using diamond anvil cells and synchrotron radiation were carried out to 20.0 GPa. Nanoparticles initially in the zinc-blende and wurtzite phases both transformed to the NaCl phase under the application of pressure. The zinc-blende particles, which were of 2.8 nm size, and the wurtzite particles, which were of 25.3 nm size, t...

A unique all-wurtzite ZnO/ZnSe hetero-nanohelix is formed via growing wurtzite ZnSe nanoteeth on ZnO nanobelts through a one step thermal evaporation method. The microstructure and growth mechanism of the hetero-nanohelix are investigated in detail. The formation of metastable wurtzite ZnSe is attributed to the wurtzite ZnO template. Mechanical forces, thermal expansion and polar plane in hexag...

Basal-plane stacking faults in wurtzite AlN, GaN, and InN are studied using density-functionalpseudopotential calculations. The formation energies follow the trend exhibited for the zinc-blende/wurtzite energy differences in the bulk materials, namely, lowest energy for GaN and highest for AlN. Type-I stacking faults have the lowest energy, followed by type-II stacking faults, and finally extri...

The theoretical models for calculations of band structure of wurtzite InN have been studied. Several models including nearly free electron model, pseudopotional method, Tight-Binding moethod and k·p method will be discussed. Currently most InN epitaxial films grown on GaN or sapphire substrate have wurtzite structure. To study the symmetry properties of the electron wave function in wurtzite st...

Bulk crystals of ZnS usually take the zinc blende structure. However, the vapor deposited one-dimensional ZnS nanostructures normally take the metastable wurtzite structure. This Letter investigates the conditions under which the formed phase can be controlled between zinc blende and wurtzite in nanomaterials synthesis. The formation of pure zinc blende structured ZnS nanobelts is related not o...

The structural, vibrational, and electronic properties of GaAs nanowires have been studied in the metastable wurtzite phase via Resonant Raman spectroscopy and synchrotron X-ray diffraction measurements in diamond anvil cells under hydrostatic conditions between 0 and 23 GPa. The direct band gap E0 and the crystal field split-off gap E0 + Δ of wurtzite GaAs increase with pressure and their valu...

We derive analytically the interface and confined polar optical-phonon modes for spherical quantum dots with wurtzite crystal structure. While the frequency of confined optical phonons in zincblende nanocrystals is equal to that of the bulk crystal phonons, the confined polar optical phonons in wurtzite nanocrystals are shown to have a discrete spectrum of frequencies different from those in bu...

Polar optical-phonon modes are derived analytically for spheroidal quantum dots with wurtzite crystal structure. The developed theory is applied to freestanding spheroidal ZnO quantum dots and to spheroidal ZnO quantum dots embedded into a MgZnO crystal. The wurtzite (anisotropic) quantum dots are shown to have strongly different polar optical-phonon modes in comparison with zincblende (isotrop...

An approach has been developed to produce CdTe films with a high proportion of the metastable wurtzite phase. It involves the use of pulsed laser deposition to produce CdTe nanoparticles which are then collected on a substrate. Electron microscopy indicates that the nanoparticles produced have a relatively minor fraction of the wurtzite phase coexisting with the stable zinc blende phase. If the...

We derive within the dielectric-continuum model an integral equation that defines interface and confined polar optical-phonon modes in nanocrystals with a wurtzite crystal structure. It is demonstrated theoretically that, while the frequency of confined polar optical phonons in zinc-blende nanocrystals is equal to that of the bulk crystal phonons, the confined polar optical phonons in wurtzite ...