Junichi Motohisa

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We report on control of growth directions of InAs nanowires on Si substrate. We achieved to integrate vertical InAs nanowires on Si by modifying initial Si(111) surface in selective-area metal-organic vapor phase epitaxy with flow-rate modulation mode at low temperature. Cross-sectional transmission electron microscope and Raman scattering showed that(More)
We report on integration of GaAs nanowire-based light-emitting-diodes (NW-LEDs) on Si substrate by selective-area metalorganic vapor phase epitaxy. The vertically aligned GaAs/AlGaAs core-multishell nanowires with radial p-n junction and NW-LED array were directly fabricated on Si. The threshold current for electroluminescence (EL) was 0.5 mA (current(More)
Highly uniform GaAs/GaAsP coaxial nanowires were prepared via selective-area metal organic vapor phase epitaxy. Photoluminescence spectra from a single nanowire indicate that the obtained heterostructures can produce near-infrared (NIR) lasing under pulsed light excitation. The end facets of a single nanowire form a natural mirror surface to create an axial(More)
Indium phosphide (InP) nanowires, which have crystal phase mixing and transition from zinc blende (ZB) to wurtzite (WZ), are grown in intermediate growth conditions between ZB and WZ by using selective-area metalorganic vapor phase epitaxy (SA-MOVPE). The shape of InP nanowires is tapered unlike ZB or WZ nanowires. A growth model has been developed for the(More)
We report a strong Kondo effect (Kondo temperature approximately 4 K) at high magnetic field in a selective area growth semiconductor quantum dot. The Kondo effect is ascribed to a singlet-triplet transition in the ground state of the dot. At the transition, the low-temperature conductance approaches the unitary limit. Away from the transition, for low bias(More)
We report on selective-area growth of vertically aligned GaAs nanowires on Si(111) substrate. Modification of the initial Si(111) surface by pretreatment under an AsH(3) atmosphere and low-temperature growth of GaAs were important for controlling the growth orientations of the GaAs nanowire on the Si(111) surface. We also found that the size of openings(More)
GaAs nanowires were selectively grown by metal-organic vapour-phase epitaxy within a SiO(2) mask window pattern fabricated on a GaAs(111)B substrate surface. The nanowires were 100-3000 nm in height and 50-300 nm in diameter. The height decreased as the mask window diameter was increased or the growth temperature was increased from 700 to 800 °C. The(More)
We propose a O(1) algorithm for bilateral filter with low memory usage. Bilateral filter can be converted into weighted histogram operation. Applying line buffers of column histograms, we can reduce the number of calculation needed to construct recursive center-weighted local histogram. Also our method have advantage in terms of memory requirements. We used(More)
We report on the fabrication of the nanowires with InGaAs/GaAs heterostructures on the GaAs(111)B substrate using selective-area metal organic vapor phase epitaxy. Fabry-Pérot microcavity modes were observed in the nanowires with perfect end facets dispersed onto the silicon substrate and not observed in the free-standing nanowires. We find that the(More)