Fujitsu Corporation

The University of Tokyo

Kenichi Kawaguchi

Tsuyoshi Takahashi

Yoshiaki Nakata

Nami Yasuoka

Hiroji Ebe

Tsuyoshi Yamamoto

Naoya Okamoto

Shinsuke Tanaka

Yasuhiko Arakawa

Ken Morito

Shoichi Miyahara

Shigeaki Sekiguchi

Ayahito Uetake

Hiroyasu Yamashita

Lei Zhu

Yusuke Kumazaki

A semiconductor device includes a plurality of tunnel diodes, each of which includes a first semiconductor region of a first conductive type and a second semiconductor region of a second conductive type that is provided above the first semiconductor region, the second semiconductor region being a nanowire shape; an insulating film provided around a side surface of the second semiconductor region; a plurality of first electrodes, each coupled to the first semiconductor region; and a plurality of second electrodes, each coupled to the second semiconductor region, wherein the second electrode has a first surface that faces the side surface of the second semiconductor region across the insulating film, and a diameter of a second semiconductor region of a first tunnel diode of the plurality of tunnel diodes is different from a diameter of a second semiconductor region of a second tunnel diode.

Semiconductor device, reservoir computing system, and method for manufacturing semiconductor device

An oscillation circuit according to the present invention includes a first oscillation circuit including a first diode having a first negative differential resistance and first composite inductor having a first inductor and a second inductor connected in series to the first diode in series. The oscillation circuit also includes a second diode that has a second negative differential resistance that is connected to the first inductor in parallel, and a third diode having a third negative differential resistance is connected to the first diode in series and is also connected to the first composite inductor in parallel. A burst pulse is output from a common connection point of the first inductor, the second inductor, and the second diode.

Oscillation circuit and information processing device

A semiconductor device includes: a first conductivity type semiconductor of a nanostructure; a first electrode that is in ohmic junction with an end part of the first conductivity type semiconductor; a second electrode that is coupled to the first electrode and is provided over a side surface of the first conductivity type semiconductor; and a depletion constituent that controls expansion of a depletion layer inside the nanostructure, wherein the depletion layer is expanded inside the first conductivity type semiconductor by the depletion constituent in a direction intersecting a movement direction of a carrier.

Semiconductor device and radio receiver using the same

A semiconductor device includes: a semiconductor layer of a first conductivity type formed over a substrate; a plurality of semiconductor nanowires formed of a compound semiconductor of the first conductivity type extending above the semiconductor layer; and a gate electrode formed around the semiconductor nanowires in a connection portion between the semiconductor layer and the semiconductor nanowires.

Semiconductor device and method for manufacturing semiconductor device

A semiconductor device includes a semiconductor substrate composed of a compound semiconductor, a first semiconductor region disposed over a surface of the semiconductor substrate so as to extend upward from the surface of the semiconductor substrate, the first semiconductor region including a semiconductor nanowire composed of a compound semiconductor, a second semiconductor region disposed over the periphery of a side surface of the first semiconductor region, a gate electrode disposed over the periphery of the second semiconductor region, a drain electrode coupled to one end of the first semiconductor region, and a source electrode coupled to another end of the first semiconductor region, the first and second semiconductor regions being composed of different semiconductor materials.

Semiconductor device

A semiconductor photodetector element includes a semiconductor substrate having a first conductivity type; a columnar structure formed on a first surface of the semiconductor substrate, the columnar structure being composed of a semiconductor of the first conductivity type; a light absorption layer formed so as to surround the columnar structure; and a semiconductor layer formed so as to surround the light absorption layer.

Semiconductor photodetector element and method

A solar cell includes a semiconductor substrate of a first conductivity; a pillar-shaped structure constituted by a semiconductor of the first conductivity, the pillar-shaped structure being formed on the semiconductor substrate; a superlattice layer including a barrier layer and a quantum structure layer that are alternately deposited on a side wall of the pillar-shaped structure, the quantum structure layer being constituted by a material having a smaller energy bandgap than that of the barrier layer, the quantum structure layer including a wurtzite type crystal part and a zinc blend type crystal part that are alternately arranged along an axial direction of the pillar-shaped structure; and a semiconductor layer of a second conductivity that is formed so as to surround the superlattice layer, the second conductivity being an opposite conductivity to that of the first conductivity.

Solar cell and manufacturing method thereof

A semiconductor laser includes a semiconductor nanowire of a first conductivity type provided over a substrate, a light emitting layer provided around the semiconductor nanowire and insulated at an upper end and a lower end thereof, a cladding layer of a second conductivity type different from the first conductivity type, the cladding layer being provided at an outer periphery of the light emitting layer, a first electrode electrically coupled to an end portion of the semiconductor nanowire, a second electrode electrically coupled to an outer periphery of the cladding layer, a first reflection mirror provided at a one-end portion side of the semiconductor nanowire, and a second reflection mirror provided at the other end portion side of the semiconductor nanowire.

Semiconductor laser

A semiconductor optical device includes a first clad layer, a second clad layer and an optical waveguide layer sandwiched between the first clad layer and the second clad layer, wherein the optical waveguide layer includes a first semiconductor layer, a second semiconductor layer disposed on the first semiconductor layer and extending in one direction, and a third semiconductor layer covering a top surface of the second semiconductor layer, and wherein the first semiconductor layer includes an n-type region disposed on one side of the second semiconductor layer, a p-type region disposed on the other side of the second semiconductor layer, and an i-type region disposed between the n-type region and the p-type region, and wherein the second semiconductor layer has a band gap narrower than band gaps of the first semiconductor layer and the third semiconductor layer.

Semiconductor optical device

A side barrier is provided between columnar dots each constituted by directly stacking respective quantum dots in seven or more layers. Out of respective side barrier layers composing the side barrier, each of the lower side barrier layers (four layers of the undermost layer to the fourth layer from the bottom) is formed as a first side barrier layer into which a tensile strain is introduced, and each of the upper side barrier layers (three layers of the fifth layer to the uppermost layer from the bottom) is formed as a second side barrier layer which has no strain.

Optical semiconductor device and manufacturing method of the same

A quantum dot semiconductor device securing sufficient gains without depending on polarization and a manufacturing method thereof. On a first barrier layer, a multilayer quantum dot is formed by repeatedly stacking alternately a quantum dot layer and a second barrier layer. On a quantum dot layer as an uppermost layer of the quantum dot, a third barrier layer which keeps local strains in the quantum dot layer is formed. On the third barrier layer, a fourth barrier layer which compensates compressive strains from the second barrier layer is formed. Therefore, the fourth barrier layer made of tensile strain materials compensates accumulation of compressive strains caused by stacking of a multilayer quantum dot layer. The third barrier layer prevents tensile strains in the fourth barrier layer from directly impacting on the quantum dot layer, so that local strains can be effectively cancelled. Thus, the above-described semiconductor device can be realized.

Semiconductor device and manufacturing method thereof

A quantum dot semiconductor device includes an active layer having a plurality of quantum dot layers each including a composite quantum dot formed by stacking a plurality of quantum dots and a side barrier layer formed in contact with a side face of the composite quantum dot. The stack number of the quantum dots and the magnitude of strain of the side barrier layer from which each of the quantum dot layers is formed are set so that a gain spectrum of the active layer has a flat gain bandwidth corresponding to a shift amount of the gain spectrum within a desired operation temperature range.

Quantum dot semiconductor device

In order to make it possible to grow up a light emitting device easily on a substrate made of a Si material system while production of an anti-phase domain can be prevented and a sufficiently high luminous efficiency can be obtained, the light emitting device is configured as a device which includes a substrate () formed from a Si material system, a SiGeC(0&#x3c;x&#x2266;1, 0&#x2266;y&#x2266;0.005) layer () and quantum dots () made of a direct transition type compound semiconductor. The quantum dots () are included in the SiGeC(0&#x3c;x&#x2266;1, 0&#x2266;y&#x2266;0.005) layer () formed on the substrate ().

Light emitting device and semiconductor device

A semiconductor quantum dot device includes: an inclined InP substrate whose principal surface normal is inclined from a [001] direction to a [1 &#x2212;10] direction in a (001) plane; and semiconductor quantum dots made of InAsSb(0&#x3c;x&#x3c;1) and disposed above the principal surface of the inclined InP substrate. Anisotropy of quantum dots is strong on the (001) plane. Anisotropy can be relaxed by using the inclined (001) substrate.

Growing community of inventors

Kawasaki, Japan

Kenichi Kawaguchi