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Evidence for the anomalous scaling behaviour of the molecular-beam epitaxy growth equation

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Chinese Physics B 2011年第3期20卷 354-359页

作者：唐刚夏辉郝大鹏寻之朋温荣吉陈玉岭 Department of Physics China University of Mining and Technology

According to the scaling idea of local slope, we investigate numerically and analytically anomalous dynamic scaling behaviour of （1＋ 1）-dimensional growth equation for molecular-beam epitaxy. The growth model includes the linear molecular-beam epitaxy （LMBE） and the nonlinear Lai-Das Sarma-Villain （LDV） equations. The anomalous scaling exponents in both the LMBE and the LDV equations are obtained, respectively. Numerical results are consistent with the corresponding analytical predictions.

关键词： molecular-beam epitaxy surface growth equation anomalous scaling behaviour

Manipulation of morphology and structure of the top of GaAs nanowires grown by molecular-beam epitaxy

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Journal of Semiconductors 2017年第10期38卷 39-45页

作者： Lixia Li Dong Pan Xuezhe Yu Hyok So Jianhua Zhao State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of Sciences College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences

Self-catalyzed GaAs nanowires（NWs） are grown on Si（111） substrates by molecular-beam epitaxy.The effect of different closing sequences of the Ga and As cell shutters on the morphology and structural phase of GaAs NWs is investigated.For the sequences of closing the Ga and As cell shutters simultaneously or closing the As cell shutter 1 min after closing the Ga cell shutter,the NWs grow vertically to the substrate surface.In contrast,when the As cell shutter is closed first,maintaining the Ga flux is found to be critical for the following growth of GaAs NWs,which can change the growth direction from [111] to 〈111〉.The evolution of the morphology and structural phase transition at the tips of these GaAs NWs confirm that the triple-phase-line shift mode is at work even for the growth with different cell shutter closing sequences.Our work will provide new insights for better understanding of the growth mechanism and realizing of the morphology and structure control of the GaAs NWs.

关键词： GaAs nanowire molecular-beam epitaxy

Electron mobility anisotropy in (Al,Ga)Sb/InAs two-dimensional electron gases epitaxied on GaAs (001) substrates

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Journal of Semiconductors 2022年第7期43卷 55-60页

作者： Qiqi Wei Hailong Wang Xupeng Zhao Jianhua Zhao State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100049China

The electron mobility anisotropy in (Al,Ga)Sb/InAs two-dimensional electron gases with different surface morphology has been investigated.Large electron mobility anisotropy is found for the sample with anisotropic morphology,which is mainly induced by the threading dislocations in the InAs layer.For the samples with isotropic morphology,the electron mobility is also anisotropic and could be attributed to the piezoelectric scattering.At low temperature (below transition temperature),the piezoelectric scattering is enhanced with the increase of temperature,leading to the increase of electron mobility anisotropy.At high temperature (above transition temperature),the phonon scattering becomes dominant.Because the phonon scattering is isotropic,the electron mobility anisotropy in all the samples would be reduced.Our results provide useful information for the comprehensive understanding of electron mobility anisotropy in the (Al,Ga)Sb/InAs system.

关键词： molecular-beam epitaxy (Al Ga)Sb/InAs two-dimensional electron gases electron mobility anisotropy piezoelectric scattering

Mn doping effects on the gate-tunable transport properties of Cd3As2 films epitaxied on GaAs

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Journal of Semiconductors 2020年第7期41卷 33-38页

作者： Hailong Wang Jialin Ma Qiqi Wei Jianhua Zhao State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering&CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China Beijing Academy of Quantum Information Sciences Beijing 100193China

The Mn doping effects on the gate-tunable transport properties of topological Dirac semimetal Cd3As2 films have been investigated.Mn-doped Cd3As2 films are directly grown on GaAs(111)B substrates by molecular-beam epitaxy,during which the single crystal phase can be obtained with Mn concentration less than 2%.Shubnikov-de Haas oscillation and quantum Hall effect are observed at low temperatures,and electrons are found to be the dominant carrier in the whole temperature range.Higher Mn content results in smaller lattice constant,lower electron mobility and larger effective band gap,while the carrier density seems to be unaffected by Mn-doping.Gating experiments show that Shubnikov-de Haas oscillation and quantum Hall effect are slightly modulated by electric field,which can be explained by the variation of electron density.Our results provide useful information for understanding the magnetic element doping effects on the transport properties of Cd3As2 films.

关键词： molecular-beam epitaxy Dirac semimetal Cd3As2 film Mn doping quantum transport

Magnetic and electrical properties of zincblende CrAs

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Chinese Physics B 2008年第6期17卷 2204-2207页

作者：陈鹏 Takamura K SouthWest University Department of Physics Research Institute of Electrical Communication Tohoku University

This paper reports that 9nm zincblende CrAs is grown by molecular-beam epitaxy on InAs buffer layer. The zb-CrAs shows ferromagnetism at room temperature and the total magnetic moment 3.09 ±0.15μB per CrAs unit. The... 详细信息

关键词： zincblende molecular-beam epitaxy half-metal

Effect of Nonradiative Recombination on Carrier Dynamics in GaInNAs/GaAs Quantum Wells

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Chinese Physics Letters 2006年第9期23卷 2566-2569页

作者：孙征王宝瑞徐仲英孙宝权姬扬倪海桥牛智川 State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences Beijing 100083

The nonradiative recombination effect on carrier dynamics in GalnNAs/GaAs quantum wells is studied by timeresolved photoluminescence （TRPL） and polarization-dependent TRPL at various excitation intensities. It is found that both recombination dynamics and spin relaxation dynamics strongly depend on the excitation intensity. Under moderate excitation intensities the PL decay curves exhibit unusual non-exponential behaviour. This result is well simulated by a rate equation involving both the radiative and non-radiative recombinations via the introduction of a new parameter of the effective concentration of nonradiative recombination centres in the rate equation. In the spin dynamics study, the spin relaxation also shows strong excitation power dependence. Under the high excitation power an increase of spin polarization degree with time is observed. This new finding provides a useful hint that the spin process can be controlled by excitation power in GaInNAs systems.

关键词： TIME-RESOLVED PHOTOLUMINESCENCE molecular-beam epitaxy GAASN ALLOYS

Magnetic characterization of a thin Co2MnSi/L10–MnGa synthetic antiferromagnetic bilayer prepared by MBE

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Chinese Physics B 2020年第10期29卷 479-483页

作者：黎姗鲁军毛思玮魏大海赵建华 State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of Sciences(CAS)Beijing 100083China Center of Materials Science and Optoelectronics Engineering&CAS Center of Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China Beijing Academy of Quantum Information Science Beijing 100193China

A synthetic antiferromagnet based on a thin antiferromagnetically coupled Co2MnSi/MnGa bilayer with Pt capping is proposed in this work. Square magnetic loops measured by anomalous Hall effect reveal that a well perpendicular magnetic anisotropy is obtained in this structure. A very large coercivity of 83 kOe (1 Oe = 79.5775 A⋅m^−1) is observed near the magnetic moment compensation point of 270 K, indicating an antiferromagnetic behavior. Moreover, the anomalous Hall signal does not go to zero even at the magnetic compensation point, for which the difficulty in detecting the conventional antiferromagnets can be overcome. By changing the temperature, the polarity of the spin–orbit torque induced switching is changed around the bilayer compensation point. This kind of thin bilayer has potential applications in spin–orbit-related effects, spintronic devices, and racetrack memories.

关键词： exchange coupling magnetization compensation anomalous Hall effect molecular-beam epitaxy

Growth and Magnetic Properties of Zincblende CrSb Epilayers on Relaxed and Strained （In, Ga）As Buffers

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Chinese Physics Letters 2006年第2期23卷 493-496页

作者：邓加军赵建华毕京峰郑玉宏贾全杰牛智川吴晓光郑厚植 State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences PO Box 912 Beijing 100083 Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences PO Box 918 Beijing 100039

Zincblende CrSb （zb-CrSb） layers with room-temperature ferromagnetism have been grown on relaxed and strained （In,Ga）As buffer layers epitaxially prepared on （001） GaAs substrates by molecular-beam epitaxy. The structural characterizations of CrSb layers fabricated under the two cases are studied by using synchrotron grazing incidence x-ray diffraction （GID）. The results of GID experiments indicate that no sign of second phase exists in all the zb-CrSb layers. Superconducting quantum interference device measurements demonstrate that the thickness of zb-CrSb layers grown on both relaxed and strained （In,Ga）As buffer layers can be increased to ～12 monolayers （～3.6nm）, compared to ,～3 monolayers （～1 nm） on GaAs directly.

关键词： ROOM-TEMPERATURE FERROMAGNETISM molecular-beam epitaxy MULTILAYER CRAS

Growth and Characterization of InN Thin Films on Sapphire by MOCVD

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Chinese Physics Letters 2007年第4期24卷 1004-1006页

作者：谢自力张荣修向前刘斌李亮韩平顾书林施毅郑有炓 Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Department of Physics Nanjing University Nanjing 210093

Indium nitride thin films are grown on sapphire substrates by metal-organic chemical vapour deposition （MOCVD） By employing three-step layer buffers, the mirror-like layers on two-inch sapphire wafers have been obtained. The structural, optical and electrical characteristics of InN are investigated by x-ray diffraction, scanning electron microscopy, atomic force microscopy, photoluminescence and infrared optical absorption. The photoluminescence and the absorption studies of the materials reveal a marked energy bandgap structure around 0.70eV at room temperature. The room-temperature Hall mobility and carrier concentration of the film are typically 939 cm^2 /Vs, and 3.9 × 1018cm^-3, respectively.

关键词： molecular-beam epitaxy LOW-TEMPERATURE BAND-GAP RF-MBE ALLOYS