Browsing by Author "Luo, Dong-Sheng"

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A delta-doped quantum well system with additional modulation doping
(2011)
Luo, Dong-Sheng
;
Lin, Li-Hung
;
Su, Yi-Chun
;
Wang, Yi-Ting
;
Peng, Zai Fong
A delta-doped quantum well with additional modulation doping may have potential applications. Utilizing such a hybrid system, it is possible to experimentally realize an extremely high two-dimensional electron gas (2DEG) density without suffering inter-electronic-subband scattering. In this article, the authors report on transport measurements on a delta-doped quantum well system with extra modulation doping. We have observed a 0-10 direct insulator-quantum Hall (I-QH) transition where the numbers 0 and 10 correspond to the insulator and Landau level filling factor nu = 10 QH state, respectively. In situ titled-magnetic field measurements reveal that the observed direct I-QH transition depends on the magnetic component perpendicular to the quantum well, and the electron system within this structure is 2D in nature. Furthermore, transport measurements on the 2DEG of this study show that carrier density, resistance and mobility are approximately temperature (T)-independent over a wide range of T. Such results could be an advantage for applications in T-insensitive devices.
Probing the onset of strong localization and electron-electron interactions with the presence of a direct insulator-quantum Hall transition
(2010-10-01)
Lo, Shun-Tsung
;
Chen, Kuang Yao
;
Lin, T. L.
;
Lin, Li-Hung
;
Luo, Dong-Sheng
We have performed low-temperature transport measurements on a disordered two-dimensional electron system (2DES). Features of the strong localization leading to the quantum Hall effect are observed after the 2DES undergoes a direct insulator-quantum Hall transition on increasing the perpendicular magnetic field. However, such a transition does not correspond to the onset of strong localization. The temperature dependences of the Hall resistivity and Hall conductivity reveal the importance of the electron-electron interaction effects for the observed transition in our study. (C) 2010 Elsevier Ltd. All rights reserved.
Probing the onset of strong localization and electron-electron interactions with the presence of a direct insulator-quantum Hall transition
(2010-10-01)
Lo, Shun-Tsung
;
Chen, Kuang Yao
;
Lin, T. L.
;
Lin, Li-Hung
;
Luo, Dong-Sheng
We have performed low-temperature transport measurements on a disordered two-dimensional electron system (2DES). Features of the strong localization leading to the quantum Hall effect are observed after the 2DES undergoes a direct insulator-quantum Hall transition on increasing the perpendicular magnetic field. However, such a transition does not correspond to the onset of strong localization. The temperature dependences of the Hall resistivity and Hall conductivity reveal the importance of the electron-electron interaction effects for the observed transition in our study. (C) 2010 Elsevier Ltd. All rights reserved.