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The electrostatic potential of the thin high-κ dielectric film and related interfaces embedded in the gate stack can be profiled in high spatial resolution in the wedge-shape sample. The retrieved potential uncovers the uneven distribution with a maximum 15.6 ± 0.7 V in HfLaON dielectric film. It implies the non-uniform material distribution in high-κ thin film and physical parameter of the film, such as permittivity, should not be considered as the constant. [ABSTRACT FROM AUTHOR]

The polarization directions of domains in BaTiO3 single crystal are determined by convergent-beam electron diffraction directly. The intensity distributions in the (001) and (001) diffraction disks are different, which is due to the noncentrosymmetric unit cell of ferroelectrics. The in situ transmission electron microscopy observations on the evolution of domains under external fields indicate that the disk with a little brighter center fringes is the (001) disk and the polarization vector is toward this disk. The method provides a straightforward criterion for polarization direction determination of ferroelectric domains. [ABSTRACT FROM AUTHOR]

Transparent cobalt doped MgO–Ga2O3–SiO2 nano-glass-ceramic composites were prepared from Si, Ga, Mg, and Co molecular precursors by a sol-gel method. X-ray diffraction patterns and transmission electron microscopy showed that the resulting material is composed of an amorphous silicate network that encloses nanocrystalline MgGa2O4 particles. Analysis of the absorption and luminescence properties indicates that Co ions are, at least partially, trapped in the crystalline phase and located in tetrahedral sites in MgGa2O4 nanocrystals. The absorption section was calculated to be 1.15×10-19 cm2. [ABSTRACT FROM AUTHOR]

The 90° domain switching in single crystalline BaTiO3 under an external static electric field has been investigated by in situ transmission electron microscopy using a special homemade transmission electron microscope stage. With the initial domains gradually disappearing, new domains that are 90° away from the initial ones are observed to occur with polarizations being switched to the direction of the external electric field, and domain boundaries being changed from (101) to (101) in order to maintain a "head-to-tail" arrangement. [ABSTRACT FROM AUTHOR]

In this letter we report the characterization of local compressive strain in p-type strained-silicon channel metal-oxide-semiconductor field effect transistors by large angle convergent-beam electron diffraction. The compressive strain was induced into the channel region of gate length of 80 nm strained-Si p-type metal-oxide-semiconductor field effect transistor by Ge preamorphization implantation for source/drain extension. A method to distinguish between compressive strain and shear strain in the cross-sectional transmission electron microscopy specimens is proposed. [ABSTRACT FROM AUTHOR]

Ferroelectric domain structure and its evolution in uniaxial relaxor Ca0.28Ba0.72Nb2O6 single crystals were investigated using transmission electron microscopy. It was found that there exists a high density of 180° domain walls in the crystals. The domains appear predominantly spike shaped along the polar axis and have a typical diameter of 50–500 nm. Domain wall motion was occasionally induced by electron beam irradiation. Macrodomains-to-microdomains switching has been observed corresponding to the normal-to-relaxor ferroelectrics transition during an in situ heating experiments. At temperature just below ferroelectric phase transition temperature TC, zero-field-cooled needlelike nanodomains were also observed. [ABSTRACT FROM AUTHOR]

Anatase Ti0.93Co0.07O2 films, synthesized by pulsed-laser deposition, have been investigated in the transmission electron microscope using selected area electron diffraction, energy dispersive x-ray analysis, and electron-energy-loss spectroscopy (EELS), and by x-ray diffraction measurements. It is found that Co ions are soluble in anatase, and that the unit-cell c-axis parameter is shortened, in some areas to even less than that in pure TiO2 anatase films. This observation was ascribed to substitution of the smaller Co3+ ions into the TiO2 anatase lattice. The EELS data confirm that Co is in either a +2 or +3 formal oxidation state in ferromagnetic Ti0.93Co0.07O2 films. [ABSTRACT FROM AUTHOR]

Aperiodic one-dimensional Si/SiO2 Thue–Morse (T–M) multilayer structures have been fabricated in order to investigate both the band gap properties with respect to the system size (band gap scaling) and the omnidirectional reflectance at the fundamental optical band gap. Variable angle reflectance data have experimentally demonstrated a large reflectance band gap in the optical spectrum of a T–M quasicrystal, in agreement with transfer matrix simulations. We explain the physical origin of the T–M omnidirectional band gap as a result of periodic spatial correlations in the complex T–M structure. The unprecedented degree of structural flexibility of T–M systems can provide an attractive alternative to photonic crystals for the fabrication of photonic devices. [ABSTRACT FROM AUTHOR]

Pt/(Ba[sub 0.7]Sr[sub 0.3])TiO[sub 3] (BST)/YBa[sub 2]Cu[sub 3]O[sub 7-x] capacitors were prepared and investigated for the dead-layer (DL) thickness (t[sub d]) and the DL dielectric constant ([variant_greek_epsilon][sub d]). Based on the series capacitor model, the t[sub d]/[variant_greek_epsilon][sub d] ratio of 0.066 nm and the bulk BST ferroelectric-layer dielectric constant of 1370 were obtained through the measurements of the capacitance–voltage characteristics. The t[sub d]×[variant_greek_epsilon][sub d] value of 120 nm was obtained through the measurements of the current–voltage characteristics. Combining these data, the DL thickness and the DL dielectric constant are respectively estimated to be 2.8 nm and 42.6. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Aligned CN[SUBx] nanotubes filled with Fe[SUB2]O[SUB3] particles were synthesized through a single pyrolysis reaction of acetonitrile and Fe[SUB2]O[SUB3]/SiO[SUB2] catalyst at 900°C under Ar[SUB2] flow. The number and spacing of the encapsulated (Fe[SUB2]O[SUB3] particles inside the CN[SUBx] nanotubes were controlled by adjusting the amount and time of acetonitrile feeding. The chemical composition and atomic structure of the nanocapsulates were investigated using combined techniques of high-resolution electron microscopy, electron energy loss spectroscopy (EELS), and elemental mapping. It was found that the encapsulated particles were (Fe[SUB2]O[SUB3] particles and that the doped nitrogen atoms, which were mainly pyridine-like, bonded with two carbon atoms within the graphene sheets, giving rise to a π*-type peak at around 399 eV in EELS spectra. [ABSTRACT FROM AUTHOR]

At room temperature, the lattice image of a modulated structure associated with charge ordering has been observed in the (La[sub 0.5]Mn[sub 0.5])MnO[sub 3] phase of La[sub 0.9]Sn[sub 0.1]MnO[sub 3], which is composed of two-type phases: ABO[sub 3] and A[sub 2]B[sub 2]O[sub 7]. Results of electron energy loss spectroscopy and energy dispersive x-ray spectroscopy show that the need of the chemical balance and small A-site radius for the (La[sub 0.5]Mn[sub 0.5])MnO[sub 3] phase are the main reasons for the appearance of charge ordering stripes. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]