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Park, Dae-Han;Kim, Nammee
- Applied Science and Convergence Technology
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- v.25 no.2
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- pp.36-41
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- 2016
Similarity and diversity of various quantum ring structures are investigated by classifying energy dispersions of three different structures: an electrostatic quantum ring, a magnetic quantum ring, and a magnetic-electric quantum ring. The wave functions and the eigenenergies of a single electron in the quantum ring structures are calculated by solving the Schrdinger equation without any electron-electron interaction. Magnetoconductance is studied by calculating a two-terminal conductance while taking into account the backscattering via the resonance through the states of the quantum rings at the center of a quasi-one dimensional conductor. It is found that the energy spectra for the various quantum ring structures are sensitive to additional electrostatic potentials as well as to the effects of a nonuniform magnetic field. There are also characteristics of similarity and diversity in the energy dispersions and in the single-channel magnetoconductance.
https://doi.org/10.5757/ASCT.2016.25.2.36 인용 PDF KSCI

Yao, Beimeng;Su, Rongbin;Wei, Yuming;Liu, Zhuojun;Zhao, Tianming;Liu, Jin
- Journal of the Korean Physical Society
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- v.73 no.10
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- pp.1502-1505
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- 2018
We present a design for hybrid circular Bragg gratings (hCBGs) for efficiently extracting single-photons emitted by InAs quantum dots (QDs) embedded in GaAs. Finite-difference time-domain simulations show that a very high photon collection efficiency (PCE) up to 96% over a 50 nm bandwidth and pronounced Purcell factors up to 19 at cavity resonance are obtained. We also systematically investigate the geometry parameters, including the $SiO_2$ thickness, grating period, gap width and the central disk radius, to improve the device performances. Finally, the PCEs and the Purcell factors of QDs located at different positions of the hCBG are studied, and the results show great robustness against uncertainties in the location of the QD.
https://doi.org/10.3938/jkps.73.1502 인용 KSCI

Shin, Y.H.;Kim, Yongmin;Song, J.D.;Choi, Subong
- Proceedings of the Korean Vacuum Society Conference
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- 2014.02a
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- pp.288.2-288.2
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- 2014
InP quantum dots were grown by using the molecular beam epitaxy technique. Quantum dots are connected and composed string-like one-dimensional structure due to the strain field along [110] crystal direction. Two prominent photoluminescence transitions from normal quantum dots and string-like one-dimensional structure were observed which show strong optical anisotropy along [1-10] and [110] crystal directions. Both peaks also showed blue-shift while rotating emission polarization from [1-10] to [110] direction. Such optical transition behaviors are the consequence of the valence band mixing caused by strain field along the [110] crystal direction.
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