Publications
ResearcherID : C-5956-2008 (TY, h-index: 24) , AAZ-8749-2021 (RK, h-index: 11)
Google Scholar : TY (h-index: 33), RK (h-index: 11)
2006
Takashi Yatsui, Motoichi Ohtsu, Sung Jin An, Jinkyoung Yoo, Gyu-Chul Yi
In: Optical Review, vol. 13, no. 4, pp. 218-221, 2006.
Abstract | Links | BibTeX | Tags: First, nanorod, Near-field spectroscopy, ZnO
@article{2006yatsuiOptRev,
title = {Evaluating the quantum confinement effect of isolated ZnO nanorod single-quantum-well structures using near-field ultraviolet photoluminescence spectroscopy},
author = {Takashi Yatsui and Motoichi Ohtsu and Sung Jin An and Jinkyoung Yoo and Gyu-Chul Yi},
doi = {10.1007/s10043-006-0218-z},
year = {2006},
date = {2006-07-01},
journal = {Optical Review},
volume = {13},
number = {4},
pages = {218-221},
publisher = {Springer Nature},
abstract = {Using low-temperature near-field spectroscopy, we obtained spatially and spectrally resolved photoluminescence (PL) images of individual ZnO nanorod single-quantum-well structures (SQWs) with a spatial resolution of 20 nm. We observed the dependence of the quantum confinement effect of the PL peak on the well width (L aw), from which the linewidths of near-field PL spectra of ZnO nanorod SQWs (L aw = 2.5 and 3.75 nm) were determined to be as narrow as 3 meV. However, near-field PL spectra of individual SQWs with L aw = 5.0 nm exhibited two PL peaks, presumably due to strains or defects in the ZnMgO in the nanorod SQWs. Since the exciton in a quantum structure is an ideal two-level system with long coherence times, our results provide criteria for designing nanophotonic devices.},
keywords = {First, nanorod, Near-field spectroscopy, ZnO},
pubstate = {published},
tppubtype = {article}
}
Using low-temperature near-field spectroscopy, we obtained spatially and spectrally resolved photoluminescence (PL) images of individual ZnO nanorod single-quantum-well structures (SQWs) with a spatial resolution of 20 nm. We observed the dependence of the quantum confinement effect of the PL peak on the well width (L aw), from which the linewidths of near-field PL spectra of ZnO nanorod SQWs (L aw = 2.5 and 3.75 nm) were determined to be as narrow as 3 meV. However, near-field PL spectra of individual SQWs with L aw = 5.0 nm exhibited two PL peaks, presumably due to strains or defects in the ZnMgO in the nanorod SQWs. Since the exciton in a quantum structure is an ideal two-level system with long coherence times, our results provide criteria for designing nanophotonic devices.
Eue-Soon Jang, Jun Young Bae, Jinkyoung Yoo, Won Il Park, Dong-Wook Kim, Gyu-Chul Yi, Takashi Yatsui, Motoichi Ohtsu
Quantum confinement effect in ZnO/Mg0.2Zn0.8O multishell nanorod heterostructures Journal Article
In: Applied Physics Letters, vol. 88, no. 2, pp. 023102, 2006.
Abstract | Links | BibTeX | Tags: MQW, Near-field spectroscopy, ZnO
@article{doi:10.1063/1.2162695,
title = {Quantum confinement effect in ZnO/Mg0.2Zn0.8O multishell nanorod heterostructures},
author = {Eue-Soon Jang and Jun Young Bae and Jinkyoung Yoo and Won Il Park and Dong-Wook Kim and Gyu-Chul Yi and Takashi Yatsui and Motoichi Ohtsu},
doi = {10.1063/1.2162695},
year = {2006},
date = {2006-01-01},
urldate = {2006-01-01},
journal = {Applied Physics Letters},
volume = {88},
number = {2},
pages = {023102},
abstract = {We report on photoluminescence measurements of Mg0.2Zn0.8O/ZnO/Mg0.2Zn0.8O multishell layers on ZnO core nanorods. Dominant excitonic emissions in the photoluminescence spectra show a blueshift depending on the ZnO shell layer thickness attributed to the quantum confinement effect in the nanorod heterostructure radial direction. Furthermore, near-field scanning optical microscopy clearly shows sharp photoluminescence peaks from the individual nanorod quantum structures, corresponding to subband levels.},
keywords = {MQW, Near-field spectroscopy, ZnO},
pubstate = {published},
tppubtype = {article}
}
We report on photoluminescence measurements of Mg0.2Zn0.8O/ZnO/Mg0.2Zn0.8O multishell layers on ZnO core nanorods. Dominant excitonic emissions in the photoluminescence spectra show a blueshift depending on the ZnO shell layer thickness attributed to the quantum confinement effect in the nanorod heterostructure radial direction. Furthermore, near-field scanning optical microscopy clearly shows sharp photoluminescence peaks from the individual nanorod quantum structures, corresponding to subband levels.
2005
Takashi Yatsui, Motoichi Ohtsu, Jinkyoung Yoo, Sung Jin An, Gyu-Chul Yi
Near-field measurement of spectral anisotropy and optical absorption of isolated ZnO nanorod single-quantum-well structures Journal Article
In: Applied Physics Letters, vol. 87, no. 3, pp. 033101, 2005.
Abstract | Links | BibTeX | Tags: First, Near-field spectroscopy, QW, ZnO
@article{doi:10.1063/1.1990247,
title = {Near-field measurement of spectral anisotropy and optical absorption of isolated ZnO nanorod single-quantum-well structures},
author = {Takashi Yatsui and Motoichi Ohtsu and Jinkyoung Yoo and Sung Jin An and Gyu-Chul Yi},
doi = {10.1063/1.1990247},
year = {2005},
date = {2005-07-01},
urldate = {2005-07-01},
journal = {Applied Physics Letters},
volume = {87},
number = {3},
pages = {033101},
abstract = {We report low-temperature near-field spectroscopy of isolated ZnO∕ZnMgO single-quantum-well structures (SQWs) on the end of ZnO nanorod to define their potential for nanophotonics. First, absorption spectra of isolated ZnO∕ZnMgO nanorod SQWs with the Stokes shift as small as 3meV and very sharp photoluminescent peaks indicate that the nanorod SQWs are of very high optical quality. Furthermore, we performed polarization spectroscopy of isolated ZnO SQWs, and observed valence-band anisotropy of ZnO SQWs in photoluminescence spectra directly. Since the exciton in a quantum structure is an ideal two-level system with long coherence times, our results provide criteria for designing nanophotonic devices.},
keywords = {First, Near-field spectroscopy, QW, ZnO},
pubstate = {published},
tppubtype = {article}
}
We report low-temperature near-field spectroscopy of isolated ZnO∕ZnMgO single-quantum-well structures (SQWs) on the end of ZnO nanorod to define their potential for nanophotonics. First, absorption spectra of isolated ZnO∕ZnMgO nanorod SQWs with the Stokes shift as small as 3meV and very sharp photoluminescent peaks indicate that the nanorod SQWs are of very high optical quality. Furthermore, we performed polarization spectroscopy of isolated ZnO SQWs, and observed valence-band anisotropy of ZnO SQWs in photoluminescence spectra directly. Since the exciton in a quantum structure is an ideal two-level system with long coherence times, our results provide criteria for designing nanophotonic devices.
2004
Takashi Yatsui, Jungshik Lim, Motoichi Ohtsu, Sung Jin An, Gyu-Chul Yi
In: Applied Physics Letters, vol. 85, no. 5, pp. 727-729, 2004.
Abstract | Links | BibTeX | Tags: First, nanorod, Near-field spectroscopy, QW, ZnO
@article{doi:10.1063/1.1776338,
title = {Evaluation of the discrete energy levels of individual ZnO nanorodsingle-quantum-well structures using near-field ultraviolet photoluminescence spectroscopy},
author = {Takashi Yatsui and Jungshik Lim and Motoichi Ohtsu and Sung Jin An and Gyu-Chul Yi},
doi = {10.1063/1.1776338},
year = {2004},
date = {2004-08-01},
urldate = {2004-08-01},
journal = {Applied Physics Letters},
volume = {85},
number = {5},
pages = {727-729},
abstract = {Spatially and spectrally resolved photoluminescence imaging of individual ZnO∕ZnMgO nanorod single-quantum-well structures (SQWs) with a spatial resolution of 55nm was performed using the optical near-field technique with a metallized UV fiber probe. Using excitation power density-dependent photoluminescence spectra of a ZnO∕ZnMgO SQW nanorod, we observed the discrete energy levels in a ZnO quantum-well layer.},
keywords = {First, nanorod, Near-field spectroscopy, QW, ZnO},
pubstate = {published},
tppubtype = {article}
}
Spatially and spectrally resolved photoluminescence imaging of individual ZnO∕ZnMgO nanorod single-quantum-well structures (SQWs) with a spatial resolution of 55nm was performed using the optical near-field technique with a metallized UV fiber probe. Using excitation power density-dependent photoluminescence spectra of a ZnO∕ZnMgO SQW nanorod, we observed the discrete energy levels in a ZnO quantum-well layer.
2002
Takashi Yatsui, Tadashi Kawazoe, Takashi Shimizu, Yoh Yamamoto, Minoru Ueda, Motonobu Kourogi, Motoichi Ohtsu, Geun-Hyoung Lee
Observation of size-dependent features in the photoluminescence of zinc oxide nanocrystallites by near-field ultraviolet spectroscopy Journal Article
In: Applied Physics Letters, vol. 80, no. 8, pp. 1444-1446, 2002.
Abstract | Links | BibTeX | Tags: First, Near-field spectroscopy, ZnO
@article{doi:10.1063/1.1453487,
title = {Observation of size-dependent features in the photoluminescence of zinc oxide nanocrystallites by near-field ultraviolet spectroscopy},
author = {Takashi Yatsui and Tadashi Kawazoe and Takashi Shimizu and Yoh Yamamoto and Minoru Ueda and Motonobu Kourogi and Motoichi Ohtsu and Geun-Hyoung Lee},
doi = {10.1063/1.1453487},
year = {2002},
date = {2002-01-01},
journal = {Applied Physics Letters},
volume = {80},
number = {8},
pages = {1444-1446},
abstract = {The optical properties of single zinc oxide (ZnO) nanocrystallites were investigated at room temperature by extending the optical near-field technique to the UV region. Using a UV fiber probe with a subwavelength aperture, we performed spatially- and spectrally-resolved photoluminescence (PL) imaging of individual ZnO nanocrystallites with a spatial resolution of 55 nm. Furthermore, decreasing the spot size increased the intensities of higher-energy components of the PL spectrum due to the quantum size effect.},
keywords = {First, Near-field spectroscopy, ZnO},
pubstate = {published},
tppubtype = {article}
}
The optical properties of single zinc oxide (ZnO) nanocrystallites were investigated at room temperature by extending the optical near-field technique to the UV region. Using a UV fiber probe with a subwavelength aperture, we performed spatially- and spectrally-resolved photoluminescence (PL) imaging of individual ZnO nanocrystallites with a spatial resolution of 55 nm. Furthermore, decreasing the spot size increased the intensities of higher-energy components of the PL spectrum due to the quantum size effect.
2001
Takashi Yatsui, Takashi Shimizu, Yoh Yamamoto, Motonobu Kourogi, Motoichi Ohtsu, Geun-Hyoung Lee
Near-field ultraviolet photoluminescence spectroscopy for evaluating the crystallinity of polycrystalline zinc oxide Journal Article
In: Applied Physics Letters, vol. 79, no. 15, pp. 2369-2371, 2001.
Abstract | Links | BibTeX | Tags: First, Near-field spectroscopy, ZnO
@article{doi:10.1063/1.1410357,
title = {Near-field ultraviolet photoluminescence spectroscopy for evaluating the crystallinity of polycrystalline zinc oxide},
author = {Takashi Yatsui and Takashi Shimizu and Yoh Yamamoto and Motonobu Kourogi and Motoichi Ohtsu and Geun-Hyoung Lee},
doi = {10.1063/1.1410357},
year = {2001},
date = {2001-10-01},
journal = {Applied Physics Letters},
volume = {79},
number = {15},
pages = {2369-2371},
abstract = {By extending the optical near-field technique to the ultraviolet region, a two-dimensional evaluation of the optical properties and crystallinity of polycrystalline zinc oxide (ZnO) was carried out at room temperature. Using an ultraviolet fiber probe with an aperture diameter of 80 nm, we obtained spatially resolved photoluminescence spectra from individual ZnO nanocrystallites; the emission intensity depended on the topography and on crystal orientation.},
keywords = {First, Near-field spectroscopy, ZnO},
pubstate = {published},
tppubtype = {article}
}
By extending the optical near-field technique to the ultraviolet region, a two-dimensional evaluation of the optical properties and crystallinity of polycrystalline zinc oxide (ZnO) was carried out at room temperature. Using an ultraviolet fiber probe with an aperture diameter of 80 nm, we obtained spatially resolved photoluminescence spectra from individual ZnO nanocrystallites; the emission intensity depended on the topography and on crystal orientation.