Abshact. The energy distribution of interface states at the insulatordilicon interface has been investigated as a function of the injected charge for standard SiOz and plasma nitrided oxides in MOS stmchues. For the nitrided samples. a lower rate of surface state generation and the absence of the midgap peak known in standard oxides was observed.
The rod shaped distribution of X-ray scattered intensity observed from the (111) surface of Si-wafer shows asymmetry in its intensity profile with respect to the Bragg point. Such asymmetry is closely related to the lattice distortion near the crystal surface. From the analysis of the observed asymmetric intensity distribution the Si lattice plane at the interface region between the Si-wafer and the adsorbed amorphous SiO2 layer is shown to be expanded by about 3% from the bulk spacing.
m e anisotropy of the inelastic mean free path (m) for electrons with energies behveen -1&lOWeV has been studied for the tint time in Re@, NaWOg and Ti0 crystals. The MFP was calculated within the one-plasmon and local density approximations from the imaginary part of the complex energy-dependent exchange and comlation potential of the Hedin-Lundqvist type. It is shown thal the MFP in compounds with a highly anisotmpic elecvon density distribution. such as ReOS and NaWOI, differs in various crystallographic directions from the MFP calculated for the averaged electmn density. In particular, it was found that m the Re03 crystal, the MFP values in (100) directions coincide with those for a spherically averaged cluster potential and are -1A smaller than in (110) and (111) directions. This result explains the variation of the outer shell amplitudes in the Re L+ge EXAFS in ReO3.
By a measurement of X-ray thermal diffuse scattering and an analysis based on a least squares fitting procedure, it was demonstrated that a set of elastic constants could be determined for an MBE grown (Ga0.5Al0.5)As mixed crystal of 4 µm thickness. The absolute value of C
11 and the ratios of the elastic constants, C
12/C
11 and C
44/C
11, were determined to be 13.32±0.35 [×1011 dyn/cm2], 0.418±0.021 and 0.473±0.013, respectively, for the sample. It turned out that the elastic constants of the mixed thin film crystal was slightly higher than that expected from the linear interpolation between GaAs and AlAs.
Although oxide crystals doped with Ce3+ are not useful in laser operation, they have advantage in the areas such as scintillators and passive optical sources. Scintillator materials require high light-yield and fast fluorescence decay time. However, when the crystalline quality is degraded by defects created during the crystal growth process, afterglow from the crystals is observable persistently. Such phosphorescence is undesirable for scintillators, but useful in passive optical sources. The phosphorescence observed in Ca2Al2SiO7 doped with Ce3+ ions has been investigated in detail and a model is proposed to explain the mechanism responsible
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