Kazuyuki Saitô

Interface‐trap generation modeling of Fowler–Nordheim tunnel injection into ultrathin gate oxide

Two mechanisms for interface‐trap generation during Fowler–Nordheim tunnel injection into gate oxide are confirmed by the results of experiments with changes in the interface‐trap density for positive and negative gate bias injections. One mechanism is independent of gate bias polarity during injection, the other mechanism is present only in negative gate bias injection. Agreements between the measured and calculated generation cross sections for both mechanisms indicate that: (i) The first mechanism is quantitatively explained using a broken‐bond model by taking account of electron heating due to an oxide field during passage through the oxide conduction band. (ii) The second mechanism is quantitatively explained using a heated electron impact model where electrons heated by the oxide field generate interface traps by directly breaking the interface weak bonds when electrons cross the interface between the SiO2 and the Si substrate.

Crystal growth of ZnxCd1−xTe solid solutions and their optical properties at the photon energies of the lowest band‐gap region

Single crystals of ZnxCd1−xTe solid solutions have been grown from a melt under an Ar pressure of about 50 atm. The crystals of uniform composition were grown over the whole range of molar composition, when the crystal growth was performed in excess Zn and/or Cd. A grown boule of 30 × 15 mm φ contained several single‐crystal domains of size 7 × 5 × 5 mm. On the basis of Vegards law, the molar composition x was determined from x‐ray measurements of lattice constants. The variation of x throughout a single‐crystal domain was found to be less than ± 1%. Optical experiments including transmittance and reflectance measurements have been made on the cleaved (110) planes at room temperature. The variation of the lowest band gap with x was determined from the peak positions in the reflectivity spectra. The bowing parameter, which is a measure of the deviation from the linear change, of this gap was found to be 0.33 eV.

Reflectivity spectra of ZnxCd1−xTe single crystals

Abstract Reflectivity measurements of the Zn x Cd1− x Te alloys were made from 2.0 to 6.2eV at room temperature. The assignments of the structures in the reflectivity spectra are made on the basis of the band gap assignments of ZnTe and CdTe. The E0, e1, and E1 gap including its spin-orbit splitting gap show the quadratic variation with molar composition, x, whereas the other gaps vary nearly linearly with x or are approximately independent of x.

C*-algebras which are Grothendieck spaces

Each monotoneσ-completeC*-algebra is a Grothendieck space.

Operator algebras and a theorem of Dieudonne

LetA be aC*-algebra with second dualA″. Let (φn)(n=1,...) be a sequence in the dual ofA such that limφn(a) exists for eacha εA. In general, this does not imply that limφn(x) exists for eachx εA″. But if limφn(p) exists whenever p is the range projection of a positive self-adjoint element of the unit ball ofA, then it is shown that limφn(x) does exist for eachx inA″. This is a non-commutative generalisation of a celebrated theorem of Dieudonné. A new proof of Dieudonné’s theorem, for positive measures, is given here. The proof of the main result makes use of Dieudonné’s original theorem.

Monotone complete C*-algebras and generic dynamics

Let S be the Stone space of a complete, non-atomic, Boolean algebra. Let G be a countably infinite group of homeomorphisms of S. Let the action of G on S have a free dense orbit. Then we prove that, on a generic subset of S, the orbit equivalence relation coming from this action can also be obtained by an action of the Dyadic Group, L Z2. As an application, we show that if M is the monotone cross product C�-algebra, arising from the natural action of G on C(S), and if the projection lattice in C(S) is countably generated then M can be approximated by an increasing sequence of finite dimensional subalgebras. On each S, in a class considered earlier, we construct a natural action of L Z2 with a free, dense orbit. Using this we exhibit a huge family of small monotone complete C � -algebras, (B�,� ∈ �) with the following properties: (i) Each Bis a Type III factor which is not a von Neumann algebra. (ii) Each Bis a quotient of the Pedersen-Borel envelope of the Fermion algebra and hence is strongly hyperfinite. The cardinality of � is 2 c , where c = 2 @0. When � 6 µ then Band Bµ take different values in the classification semi-group; in particular, they cannot be isomorphic.

Extending a result of Ryan on weakly compact operators

An elegant result of Ryan gives a characterization of weakly compact operators from a Banach space

A bounded sequence of normal functionals has a subsequence which is nearly weakly convergent

A

On σ-Normal C*-Algebras

into

Ideals of factors

c_{0}(X)