Search

Your search keyword '"Igarashi, Makoto"' showing total 5 results
Start Over Author "Igarashi, Makoto" Topic photoluminescence
5 results on '"Igarashi, Makoto"'

2. Quantum size effects in GaAs nanodisks fabricated using a combination of the bio-template technique and neutral beam etching

Author

Tamura, Yosuke, Kaizu, Toshiyuki, Kiba, Takayuki, Igarashi, Makoto, Tsukamoto, Rikako, Higo, Akio, Hu, Weiguo, Thomas, Cedric, Fauzi, Mohd Erman, Hoshii, Takuya, Yamashita, Ichiro, Okada, Yoshitaka, Murayama, Akihiro, and Samukawa, Seiji

Subjects
Photoluminescence, Nanostructure, Materials science, Bioengineering, Gallium, Electron, Arsenicals, Polyethylene Glycols, Optics, Etching (microfabrication), Quantum Dots, Nanotechnology, General Materials Science, Scanning, Electrical and Electronic Engineering, Particle Size, Deposition (law), Microscopy, business.industry, Mechanical Engineering, General Chemistry, Nanostructures, Mechanics of Materials, Quantum dot, Ferritins, Microscopy, Electron, Scanning, Optoelectronics, Luminescence, business, Beam (structure), Surface finishing, Biotechnology
Abstract

We successfully fabricated defect-free, distributed and sub-20-nm GaAs quantum dots (named GaAs nanodisks (NDs)) by using a novel top-down technique that combines a new bio-template (PEGylated ferritin) and defect-free neutral beam etching (NBE). Greater flexibility was achieved when engineering the quantum levels of ND structures resulted in greater flexibility than that for a conventional quantum dot structure because structures enabled independent control of thickness and diameter parameters. The ND height was controlled by adjusting the deposition thickness, while the ND diameter was controlled by adjusting the hydrogen-radical treatment conditions prior to NBE. Photoluminescence emission due to carrier recombination between the ground states of GaAs NDs was observed, which showed that the emission energy shift depended on the ND diameters. Quantum level engineering due to both diameter and thickness was verified from the good agreement between the PL emission energy and the calculated quantum confinement energy.

Published
2013

3. Photoluminescence from GaAs nanodisks fabricated by using combination of neutral beam etching and atomic hydrogen-assisted molecular beam epitaxy regrowth.

Author

Kaizu, Toshiyuki, Tamura, Yosuke, Igarashi, Makoto, Hu, Weiguo, Tsukamoto, Rikako, Yamashita, Ichiro, Samukawa, Seiji, and Okada, Yoshitaka

Subjects
SUPERLATTICES, PHOTOLUMINESCENCE, MOLECULAR beam epitaxy, ATOMIC hydrogen, SCANNING electron microscopy
Abstract

We have fabricated GaAs nanodisk (ND) structures by using a combination of neutral beam etching process and atomic hydrogen-assisted molecular beam epitaxy regrowth. We have observed clear photoluminescence (PL) emissions from GaAs NDs. The peak energy showed a blueshift due to the quantum confinement in three spatial dimensions, and it agreed with the theoretically estimated transition energy. The PL results also showed that the cap-layer disks act as radiative recombination centers. We have confirmed that the PL emission originates from the GaAs NDs, and our approach is effective for the fabrication of high quality ND structures. [ABSTRACT FROM AUTHOR]

Published
2012
Full Text
View/download PDF

4. Picosecond transient photoluminescence in high-density Si-nanodisk arrays fabricated using bio-nano-templates.

Author

Kiba, Takayuki, Mizushima, Yoshiya, Igarashi, Makoto, Huang, Chi-Hsien, Samukawa, Seiji, and Murayama, Akihiro

Subjects
NANOSILICON, PHOTOLUMINESCENCE, SILICON, NANOSTRUCTURED materials, CHARGE exchange
Abstract

We study picosecond transient photoluminescence (PL) in Si-nanodisk (Si-ND) arrays fabricated using bio-nano-templates. The PL time profiles show multi-exponential decaying kinetics depending on the disk density. We attribute the fastest decaying component with a decay time of 40 ps observed only in the high-density Si-ND array to the electron transfer among the Si-NDs. [ABSTRACT FROM AUTHOR]

Published
2012
Full Text
View/download PDF

5. Surface/interface-related optical properties in Si nanodisks fabricated by neutral-beam etching using bio-templates.

Author

Kiba, Takayuki, Suzaki, Kenta, Li, Hao, Igarashi, Makoto, Samukawa, Seiji, and Murayama, Akihiro

Subjects
*OPTICAL properties of silicon, *SURFACE energy, *PHOTOLUMINESCENCE, *CHEMICAL templates, *CRYSTAL etching, *QUANTUM states, *TEMPERATURE effect, *NEUTRAL beams
Abstract

Abstract: The authors study surface/interface-related optical properties in Si nanodisks (NDs) fabricated by neutral-beam etching using bio-templates. Photoluminescence (PL) spectra and the transient properties are compared between different barrier materials of SiO2 and SiC. The PL spectral shape depends on the barrier material, indicating effects of oxide formation and/or oxygen atoms on the surface of the Si ND. The transient PL shows nanosecond-scale transition of carriers in surface-related quantum states in the ND. Temperature dependences of the PL intensity show that the activation energy responsible for the electron escape from the Si-ND at near room temperature in the case of SiC barrier agrees well with the conduction band offset, whereas that in the case of SiO2 barrier is significantly lower than the expected offset. The latter discrepancy suggests that the electronic band structure at the interface of Si-ND/SiO2 can be largely affected by dielectric screening due to oxygen atoms in the SiO2. [Copyright &y& Elsevier]

Published
2013
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results