Single-crystal thin films of Pb(ZrxTi1−x)O3 (PZT) covering the full compositional range (0⩽x⩽1) were deposited by metal-organic chemical vapor deposition. Epitaxial SrRuO3(001) thin films grown on SrTiO3(001) substrates by rf-magnetron sputter deposition served as template electrode layers to promote the epitaxial growth of PZT. X-ray diffraction, energy-dispersive x-ray spectroscopy, atomic force microscopy, transmission electron microscopy, and optical waveguiding were used to characterize the crystalline structure, composition, surface morphology, microstructure, refractive index, and film thickness of the deposited films. The PZT films were single crystalline for all compositions exhibiting cube-on-cube growth epitaxy with the substrate and showed very high degrees of crystallinity and orientation. The films exhibited typical root mean square surface roughness of ∼1.0–2.5 nm. For tetragonal films, the surface morphology was dominated by grain tilting resulting from ferroelectric domain formation. We report the systematic compositional variation of the optical, dielectric, polarization, and electronic transport properties of these single-crystalline PZT thin films. We show that the solid-solution phase diagram of the PZT system for thin films differs from the bulk due to epitaxy-induced strains and interfacial defect formation. High values of remanant polarization (30–55 μC/cm2) were observed for ferroelectric compositions in the range of 0.8⩽x⩽0.2. Unlike previous studies, the dielectric constant exhibited a clear dependence on composition with values ranging from 225 to 650. The coercive fields decreased with increasing Zr concentration to a minimum of 20 kV/cm for x=0.8. The undoped films exhibited both high resistivity and dielectric-breakdown strength (1013–1014 Ω cm at 100 kV/cm and 300–700 kV/cm, respectively).

No abstract

Nanometer size polarized domains were written in a PbZr1−xTixO3 (PZT) thin film using an atomic force microscope (AFM) and the relationship between the polarized domain and the grain of the film was investigated. The polarized domain was formed by applying a pulse voltage to the ferroelectric PZT thin film through a conductive AFM tip. The polarized domain structure was observed by imaging the piezoelectric-induced surface vibration by an AFM with an ac voltage applied between the tip and the bottom electrode of a sample. The polarized domains with a diameter of 50 nm were written within a single grain.

The diffusivity of 3 He atoms in perfect crystals of tungsten has been studied employing the atomprobe field-ion microscope (FIM) technique. Tungsten FIM specimens were implanted in situ with 300-eV 3He+ ions, to a fluence of 3 X lOIS ions cm -2, at specimen temperatures which ranged from 60 to 110 K. The 3He + ion beam was analyzed magnetically and the ion source was connected to the atom probe through a differentially pumped aperture. At an implantation energy of 300 eV no radiation damage was produced by the implanted 3He atoms. Thus, the state of a tungsten specimen after an implantation consisted of 3 He atoms with an initial depth distribution that was determined solely by the range profile of the low-energy ions. Isothermal annealing experiments between 90 and 110 K were employed to study the kinetics of recovery of the implanted 3He atoms; at 60 K the 3He atoms are immobile. This data, in combination with a suitable diffusion model, was used to determine-for the first time-the diffusivity [D'He (T)] and the enthalpy change of migration of 3 He atoms (.::1h ~e ) in tungsten. The quantity D'He(T) is given by the Arrhenius expression: D'He(T) = (5.4 ± ~086)x 10-3 exp( -0.28 eV /kT}cm2 S-I.The value of.::1h ~e is approximately the same as for.::1h ~e (0.24--0.32 eV). D'He (T) is compared with the diffusivity values of IH and self-interstitial atoms in tungsten-the self-interstitial atoms are considerably more mobile than 3He or 4He atoms at the same temperature, as are the IH atoms.

The heteroepitaxial growth of III-V compound semiconductors on Si would enable the integration of high-performance III-V materials with Si technology. We report epitaxial growth on (111)-oriented Si surfaces of highly aligned, single crystalline InP nanowires by chemical vapor deposition catalyzed by Au. We demonstrate laterally oriented InP nanowires bridging between vertical (111) Si surfaces formed by anisotropically etching a (110)-oriented Si substrate or the top Si layer of a silicon-on-insulator wafer. This method of connecting nanowires offers a facile way of integrating nanoscale III-V optoelectronic and photonic devices with Si.