A signal detection system using noise statistical processing is proposed. By approaching the problems of low voltage and high noise from miniaturization of a device from a stochastic point of view, a faint-signal receiving system that can effectively detect subthreshold and noise level signals has been developed. In addition, an alternative to statistical processing is proposed, and would be successfully implemented on a circuit. For the proposed signal detection method, the detection sensitivity was investigated using numerical simulation, and the detection sensitivity was sufficiently high to detect even a signal with a signal-to-inherent-noise ratio of −14 dB. Thus, it is anticipated that the application of this system to an integrated circuit will have a significant impact on signal processing.

Temperature dependence of the electron mobility in modulation-doped InGaAs/InAlAs single heterostructures has been investigated by Hall effect measurements in the temperature range from 15 K to 300 K in order to clarify the scattering mechanisms of the electrons. Two kinds of samples are used with doping densities in the InAlAs barrier layer, N D=3×1017 cm-3 and 1×1018 cm-3. The measured electron mobility is compared with the calculated values by taking into account the scattering by InAs-like and GaAs-like LO phonons in the InGaAs channel layer, in addition to the acoustic deformation potential, piezoelectric, ionized impurity, alloy disorder and interface roughness scatterings. The calculated electron mobility shows a good agreement with the experimental data when the alloy disorder potential is assumed to be about 0.7 eV.

A structurally constrained S,C,C-bridged triphenylamine was synthesized, and the corresponding radical cation was obtained as a hexachloroantimonate by chemical oxidation. An X-ray crystallographic analysis revealed an almost planar structure for this radical cation, which thus represents the first example of a planar, para-unsubstituted triphenylamine radical cation analogue with a sulfur bridge. The electronic properties of the radical cation were examined by UV–vis–NIR and ESR spectroscopy as well as DFT calculations.

In addition to being initially developed as an energy driver for an inertial confinement fusion, an intense, pulsed, light-ion beam (LIB) has been found to be applied to materials science. If a LIB is used to irradiate targets, a high-density ‘‘ablation’’ plasma is produced near the surface since the range of the LIB in materials is very short. Since the first demonstration of quick preparation of thin films of ZnS by an intense, pulsed, ion-beam evaporation (IBE) using the LIB-produced ablation plasma, various thin films have been successfully prepared, such as of ZnS:Mn, YBaCuO, BaTiO3, cubic BN, SiC, ZrO2, ITO, B, C, and apatite. Some of these data will be presented in this paper, with its analytic solution derived from a one-dimensional, hydrodynamic, adiabatic expansion model for the IBE. The temperature will be deduced using ion-flux signals measured by a biased ion collector. Reasonable agreement is obtained between the experiment and the simulation. High-energy LIB implantation to make chemical compounds and the associated surface modification are also discussed.

An ultralow power constant reference current circuit with low temperature dependence for micropower electronic applications is proposed in this paper. This circuit consists of a constant-current subcircuit and a bias-voltage subcircuits, and it compensates for the temperature characteristics of mobility µ, thermal voltage V T , and threshold voltage V T H in such a way that the reference current has small temperature dependence. A SPICE simulation demonstrated that reference current and total power dissipation is 97.7 nA, 1.1 µW, respectively, and the variation in the reference current can be kept very small within ±4% in a temperature range from −20 to 100 • C.