http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Magnetotransport Measurements on an AlGaN/GaN Two-Dimensional Electron System
Jyun-Ying Lin,C.-T. Liang,전창민,D.~H. Youn,김길호,H. Park,백정민,Jing-Han Chen,이종람,Y. F. Chen 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.3
We report on the transport properties of an AlGaN/GaN two-dimensional electron system in the presence of a perpendicular magnetic field B. At low magnetic fields, the measured longitudinal resistivity xx shows a B2 dependence at various temperatures. This eect can be ascribed to electron-electron interaction eects in a weakly disordered electron system. At high magnetic fields, there is a temperature-independent point in xx at the critical magnetic field Bc. We find that at this crossing point, the Hall-resistivity xy is approximately equal to xx. By analyzing the amplitude of the observed Shubnikov-de Hass oscillations at high fields, we find that at the crossing point, µqB = 0.17 < 1, where µq is the quantum mobility. Within the Drude-Boltzman theory, µq should be approximately equal to µ. The fact that µq < µ could be due to a high-field localization eect which gives rise to the formation of a quantum Hall liquid-like state because xx increases with increasing temperature for B > Bc.
A study on microstructural and dielectric properties of Ba0.5-xZnxSr0.45Ca0.05TiO3 ceramics
Ying-Chieh Lee,Hui-Ju Hsu,I-Yu Huang,Huei-Jyun Shih,Christian Pithan 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.6
reaction process and sintered at temperatures ranging from 1150 °C to 1250 °C. The properties of these ceramics werefound to be significantly affected by variations in the Zn content. Densification of the BZSCT ceramics was observed to occurat sintering temperatures exceeding 1225 °C. Notably, the crystalline phases and dielectric properties of these ceramics werestrongly influenced by the Zn content. Three distinct secondary phases were identified in the BZSCT ceramics, includingBaZn2.03Ti3.93O10.89, Ba2ZnTi5O13 and Zn2TiO4. The addition of Zn resulted in a shift of the Curie point to lower temperatures. Specifically, with Zn substitution (up to 15 at.%), a Curie point of -60 °C was observed in the BZSCT ceramics. Theseceramics exhibited a high dielectric constant of 1035, a low dielectric loss of 0.017%, and an impressive Q value of 442 whensintered at 1225 °C. Moreover, when comparing the dielectric constants of BZSCT ceramics at 1 MHz and 1 GHz, it wasnoted that the permittivity was only slightly reduced by less than 30% at lower frequencies. In contrast, the permittivity ofBST ceramics decreased significantly, by approximately 70%, at microwave frequencies. These findings highlight the uniqueproperties and potential applications of BZSCT ceramics, particularly in microwave applications where they outperformtraditional BST ceramics.
E.S Kannan,Gil Ho Kim,D. H. Youn,Chi-Te Liang,Jing-Han Chen,Jyun-Ying Lin,Kuang Yao Chen,Kwang-Yong Kang,Li-Hung Lin,N.C. Chen,Zhi-Yao Zhang 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.6
We report comparative magnetoresistance measurements of the two-dimensional electron gas formed in two different GaN/AlGaN quantum well structures with different starting disorder. The longitudinal magnetoresistance measurements for both the samples exhibited temperature-independent crossing points, evidence for a weak insulator - quantum Hall transition. Our data suggest that the onset of Landau quantization does not correspond to the crossing point. Moreover, the effect of the electron-electron interaction must be taken into account because the Hall resistivity shows a strong temperature dependence in the more disordered sample. Our experimental results, therefore, urge further studies on the low-field weak insulator - quantum Hall transition
Jing-Han Chen,Chi-Te Liang,Chun-Feng Huang,Da-Ren Hang,David A. Ritchie,J. C. Hsiao,Jyun-Ying Lin,Michelle Y. Simmons,Ming-Gu Lin,S. H. Lo,Tsai-Yu Huang 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.3
By applying a magnetic field perpendicular to GaAs/AlGaAs two-dimensional electron systems (2DESs), we study the low-field Landau quantization when the thermal damping is reduced with decreasing temperature. Magneto-oscillations following the Shubnikov-de Haas (SdH) formula are observed even when their amplitudes are so large that the deviation to such a formula is expected. Our experimental results show the importance of the positive magneto-resistance to the extension of the SdH formula under the damping induced by the disorder.
Jing-Han Chen,C.-T. Liang,D.H. Youn,Eun-Jin Lee,Gil-Ho Kim,Hun Park,Hyun-Ick Cho,Jung-Hee Lee,Jung-Kai Tsai,Jyun-Ying Lin,Y. F. Chen 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.6
AlGaN/GaN heterostructures have been attracting a great deal of interest because of their great potential applications as light-emitting-diodes, high-electron-mobility transistors (HEMTs), and detectors operating in the visible-to-ultraviolet range. The performances of these devices are governed by the electronic properties of the two-dimensional electron gas (2DEG) formed at the interface of AlGaN/GaN heterostructure. In this work, we report transport measurements for an AlGaN/GaN 2DEG as functions of the magnetic field B over a wide range of temperature (4.682 K T 80 K). At the highest measurement temperature of 80 K, the longitudinal resistance is nominally Bindependent, compelling experimental evidence for Drude-Boltzmann-like transport in a 2D system.