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Magnetic field and temperature dependence of the properties of the ground state of the strong-coupling bound magnetopolaron in quantum rods with hydrogenic impurity

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Journal of Semiconductors 2013年第5期34卷 1-6页

作者：辛伟赵玉伟韩超额尔敦朝鲁 Institute of Condensed Matter Physics Hebei Normal University of Science & Technology

Magnetic field and temperature dependence of the properties of the ground state of the strong-coupling bound magnetopolaron in quantum rods （QRs） with hydrogenic impurity is studied by means of the Huybrechts- Lee-Low-Pines transformation method and the quantum statistical theory. The expressions for the ground-state energy and the mean number ofphonons of the magnetopolaron are derived. Results of the numerical calculations show that the bound state of the magnetopolaron cannot be formed when the value of the aspect ratio of the QR, the dielectric constant ratio, the electron-phonon coupling strength or the temperature parameter is small. The larger the deviation of the value of aspect ratio e′ from 1 is, the more it is unfavorable to the stability of the ground state of the magnetopolaron. When the magnetopolaron is in the bound state, the absolute value of its ground-state energy and its mean number ofphonons increase with an increase of the dielectric constant ratio and confinement strength of QRs, but decrease with an increase in the cyclotron frequency of the external magnetic field and the temperature. The absolute value of the ground-state energy and the mean number of phonons of the magnetopolaron decrease with decreasing e′ when e′ 〈 1, but decrease with increasing e′ when e′ 〉 1. They get the maximum value at e′=1.

关键词： quantum rods hydrogenic impurity magnetopolaron ground-state energy mean number ofphonons temperature dependence

Linear-Polarization Optical Property of CdSe quantum rods

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Journal of Semiconductors 2006年第12期27卷 2094-2100页

作者：张秀文夏建白中国科学院半导体研究所北京100083

The linear-polarization optical property of CdSe quantum rods is studied in the framework of effectivemass envelope function theory. The effects of shape and magnetic field on the linear polarization factors are investigated. It is found that CdSe quantum spheres have negative polarization factors （xy-polarized emission）and quantum long rods with small radius have positive linear polarization factors （z-polarized emission）. The z-direction is the direction of the c axis. quantum long rods with large radius have negative linear polarization factors,due to the hexagonal crystal symmetry and the crystal field splitting energy. The linear polarization factors decrease and may change from a positive value to a negative value;i, e. ,the z-polarized emissions decrease relative to xy-polarized emissions as the magnetic field applied along the z direction increases.

关键词： quantum rods linear oolarization. CdSe

Photo-induced flexible semiconductor CdSe/CdS quantum rods alignment

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半导体学报:英文版 2023年第9期44卷 83-89页

作者： Wanlong Zhang Julian Schneider Maksym F.Prodanov Valerii V.Vashchenko Andrey L.Rogach Xiaocong Yuan Abhishek K.Srivastava Nanophotonics Research Center Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China State Key Laboratory of Advanced Displays and Optoelectronics Technologies Department of Electronic&Computer EngineeringHong Kong University of Science and TechnologyHong Kong SARChina Department of Materials Science and Engineering and Centre for Functional Photonics(CFP) City University of Hong KongHong Kong SARChina

The anisotropic absorption and emission from semiconductor CdSe/CdS quantum rods(QRs)provide extra benefits among other photoluminescence *** photo-induced alignment technique,the QRs can be oriented in liquid crystal polymer matrix at a large *** this article,a 2D Dammann grating pattern,within“SKL”characters domains aligned QRs in composite film,was fabricated by multi-step photo exposure using several photo masks,and a continuous geometric lens profile pattern aligned QRs was realized by the single step polarization converting holographic irradiation *** polarized optical microscope and fluorescence microscope are employed to determine the liquid crystal director profiles and QRs anisotropic excitation *** have been able to orient the QRs in fine binary and continuous patterns that confirms the strong quantum rod aligning ability of the proposed ***,the proposed approach paves a way for photoinduced flexible QRs alignments to provide a highly specific and difficult-to-replicate security application at a large scale.

关键词： quantum rods photo alignment liquid crystal flexible alignment polarized emission

Nanoseparation-lnspired Manipulation of the Synthesis of CdS Nanorods

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Nano Research 2011年第2期4卷 226-232页

作者： Xiaoming Sun Xiuju Ma Lu Bai Junfeng Liu Zheng Chang David G. Evans Xue Duan Jiaou Wang Joseph F. Chiang State Key Laboratory of Chemical Resource Engineering RO. Box 98 Beijing University of Chemical Technology Beijing 100029 China Institute of High Energy Physics Beijing 100039 China Department of Chemistry and Biochemistry SUNY-Oneonta Oneonta NY 13820 USA

CdS nanorods have been sorted by length using a density gradient ultracentrifuge rate separation method. The fractions containing longer rods showed relatively stronger oxygen-related surface trap emission, while the shorter ones had dominant band-edge emission. These results suggest that the final length distribution of CdS nanorods is not a result of random nucleation and growth, but is related to the local synthesis conditions. Inspired by these findings, different synthesis environments （N2, air, and 02） have been employed in order to tailor the length distribution. In addition to the rod length, the photoluminescence properties of CdS nanorods can also be manipulated. Increasing the oxygen partial pressure significantly changed the growth behavior of CdS nanorods by improving the anisotropic growth.

关键词： Nanoseparation quantum rods CdS photoluminescence controlled synthesis