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稀磁半导体制备方法与磁性起源的研究是当前凝聚态物理的一项热门课题.首先介绍了自燃烧合成法的原理和优点,然后以Co和Mn掺杂ZnO为重点,总结了国内外采用自燃烧法合成的ZnO基稀磁半导体纳米颗粒晶体结构、磁性能相关的研究进展,讨论了所得纳米颗粒磁性能的内在物理机制.通过对自燃烧法合成的更宽掺杂范围ZnO基稀磁半导体纳米颗粒的研究,使我们能够更加系统地了解过渡金属掺杂ZnO材料的结构与磁性能,并探讨所得实验现象的内在物理机制. 相似文献
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ZnO是一种宽带隙Ⅱ-Ⅵ族半导体,具有良好的光电耦合特性和稳定性,在光、电、磁功能集成等新型器件方面可获得重要应用.近来的研究表明,过渡金属掺杂的ZnO基半导体有望成为实现高居里温度稀磁半导体的候选材料,是目前研究的热点.总结了近几年人们在Fe、Co、Ni、Cu、Mn等过渡金属掺杂的ZnO基稀磁半导体的发光特性研究结果,讨论了过渡金属掺杂后ZnO中观察到的可见发光机制,分析认为过渡金属掺杂ZnO的可见光发射主要与这些发光过渡金属引入后所产生的缺陷有关,而紫外发光峰的变化则与过渡金属掺入后ZnO晶体质量与禁带宽度的改变相关. 相似文献
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在(0001)面的蓝宝石衬底上用低压MOCVD法生长p型GaN外延层.对p型GaN薄膜用180keV的Mn 离子注入进行磁性粒子掺杂,注入时GaN薄膜处于300℃,注入剂量分别为5.0×1015、1.0×1016和5.0×1016cm-2.对注入的样品在N2气流中进行快速热退火处理,温度为850℃,时间为30s.用超导量子干涉仪(SQUID)对样品的磁性进行了分析,在5.0×1015cm-2的注入样品中发现了较强的铁磁性;而1.0×1016和5.0×1016cm-2的Mn 离子注入样品中铁磁响应有所减弱.结合用X射线衍射(XRD)和扫描电子显微镜(SEM)对在不同剂量下Mn 注入GaN薄膜的结构、形貌和成分的分析,揭示了不同剂量磁性离子注入给GaN薄膜带来的结构、形貌和相应的铁磁性变化规律,发现只有适当的注入剂量(5.0×1015cm-2)才有利于在300℃下用180keV的Mn 注入对p型GaN薄膜进行磁性离子掺杂. 相似文献
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Mn+离子注入GaN薄膜的磁性研究 总被引:1,自引:1,他引:0
在(0001)面的蓝宝石衬底上用MOCVD法生长纤锌矿结构的GaN.GaN膜总厚度为4μm,表层为0.5μm厚的掺Mg的p型层.用90keV的Mn+离子对处于室温下的GaN进行离子注入,注入剂量为1×1015~5×1016ions/cm2.对注入的样品在N2气流中经约800℃进行快速热退火处理,时间为30~90s.样品的磁性用超导量子干涉仪(SQUID)进行分析.未注入的p型GaN薄膜是抗磁性的,而Mn+注入的GaN显现顺磁性(注入剂量为1×1015ions/cm2)和铁磁性(注入剂量为5×1015~5×1016ions/cm2).结合X射线衍射(XRD)和扫描电子显微镜(SEM)对GaN薄膜在注入和退火后的结构和形貌研究,揭示Mn+ 注入是进行GaN磁性掺杂的有效手段,在Mn+ 注入p型GaN、制备得到的(Ga,Mn)N稀磁半导体中,空穴调制铁磁性是其主要的磁性机制. 相似文献
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稀磁半导体(DMSs)材料同时利用了电子的电荷属性和自旋属性,具有优异的磁、磁光、磁电等性能,在材料学和未来自旋电子器件领域具有广阔的应用前景。本文综合述评了近几年来ZnO基稀磁半导体纳米材料研究的进展概况,并简介了DMSs器件的潜在应用。 相似文献
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A new III–V nitride-based diluted magnetic semiconductor GaCrN has been successfully synthesized for the first time. X-ray diffraction measurement showed no existence of secondary phase in the GaCrN layers. They showed a ferromagnetic behavior with the Curie temperature of higher than 400 K, and clear saturation and hysteresis were observed in the magnetization versus magnetic field curves at all measuring temperatures (10–400 K). Specially, GaCrN magnetization data show no paramagnetic component at low temperature, which are superior characteristics over GaMnN. Photoluminescence emission from GaCrN layer was observed at around 3.29 eV at 10–300 K. 相似文献
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Xing Guo Gao Bao Yuan Man Mei Liu Cheng Yang Chuan Song Chen Shou Zhen Jiang Chun Ming Wang 《Journal of Superconductivity and Novel Magnetism》2013,26(12):3495-3499
GaMnN thin films were fabricated by using pulsed laser deposition followed by annealing. In our experiments, the impact of the background nitrogen pressure on the crystal quality, morphology and the ferromagnetism of the GaMnN thin films were studied systematically. It is found that the samples deposited at 0.75 Pa have the best crystal quality. All the annealed samples showed ferromagnetic behavior, and the Curie temperature was estimated up to 340 K. We found the magnetization of our samples changes depending on the concentration of Mn3+ ions, and the origin of the room temperature ferromagnetism of our samples can be explained by bound magnetic polaron theory. The nitrogen vacancies may cause the ferromagnetism to be weakened. 相似文献
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Semiconductor nanostructures show many special physical properties associated with quantum confinement effects, and have many applications in the opto-electronic and microelectronic fields. However, it is difficult to calculate their electronic states by the ordinary plane wave or linear combination of atomic orbital methods. In this paper, we review some of our works in this field, including semiconductor clusters, self-assembled quantum dots, and diluted magnetic semiconductor quantum dots. In semiconductor clusters we introduce energy bands and effective-mass Hamiltonian of wurtzite structure semiconductors, electronic structures and optical properties of spherical clusters, ellipsoidal clusters, and nanowires. In self-assembled quantum dots we introduce electronic structures and transport properties of quantum rings and quantum dots, and resonant tunneling of 3-dimensional quantum dots. In diluted magnetic semiconductor quantum dots we introduce magnetic-optical properties, and magnetic field tuning of the effective g factor in a diluted magnetic semiconductor quantum dot. 相似文献
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以氧化物宽禁带半导体为基体,通过掺杂磁性元素,可将非磁性半导体转变成铁磁性半导体,利用这些铁磁性半导体,能将新型的自旋电子器件集成到传统的微电子器件上,构成功能丰富的新型器件.由于稀磁半导体材料在自旋电子学中的重要作用,近年来受到广泛的关注.简要总结了有关氧化物稀磁半导体研究的发展状况;分析了制备条件对其磁性的可能影响;重点介绍了该系统中有关磁性起源的理论模型,包括双交换机制、磁极化子模型、RKKY模型等;比较了2种磁极化子理论模型,并对这些模型的适用范围进行了分析讨论.另外,还介绍了该体系微结构和磁结构的一些检测方法以及与磁性相关的输运性质、反常霍尔效应等. 相似文献
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Stolichnov I Riester SW Trodahl HJ Setter N Rushforth AW Edmonds KW Campion RP Foxon CT Gallagher BL Jungwirth T 《Nature materials》2008,7(6):464-467
Multiferroic structures that provide coupled ferroelectric and ferromagnetic responses are of significant interest as they may be used in novel memory devices and spintronic logic elements. One approach towards this goal is the use of composites that couple ferromagnetic and ferroelectric layers through magnetostrictive and piezoelectric strain transmitted across the interfaces. However, mechanical clamping of the films to the substrate limits their response. Structures where the magnetic response is modulated directly by the electric field of the poled ferroelectric would eliminate this constraint and provide a qualitatively higher level of integration, combining the emerging field of multiferroics with conventional semiconductor microelectronics. Here, we report the realization of such a device using (Ga,Mn)As, which is an archetypical diluted magnetic semiconductor with well-understood carrier-mediated ferromagnetism, and a polymer ferroelectric gate. Polarization reversal of the gate by a single voltage pulse results in a persistent modulation of the Curie temperature of the ferromagnetic semiconductor. The non-volatile gating of (Ga,Mn)As has been made possible by applying a low-temperature copolymer deposition technique that is distinct from pre-existing technologies for ferroelectric gates on magnetic oxides. This accomplishment opens a way to nanometre-scale modulation of magnetic semiconductor properties with rewritable ferroelectric domain patterns, operating at modest voltages and subnanosecond times. 相似文献
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Zaleszczyk W Janik E Presz A Dłuzewski P Kret S Szuszkiewicz W Morhange JF Dynowska E Kirmse H Neumann W Petroutchik A Baczewski LT Karczewski G Wojtowicz T 《Nano letters》2008,8(11):4061-4065
It is shown that the growth of II-VI diluted magnetic semiconductor nanowires is possible by the catalytically enhanced molecular beam epitaxy (MBE). Zn(1-x)MnxTe NWs with manganese content up to x=0.60 were produced by this method. X-ray diffraction, Raman spectroscopy, and temperature dependent photoluminescence measurements confirm the incorporation of Mn(2+) ions in the cation substitutional sites of the ZnTe matrix of the NWs. 相似文献
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The observation of ferromagnetism in magnetic ion doped II–VI diluted magnetic semiconductors (DMSs) and oxides, and later
in (Ga,Mn)As materials has inspired a great deal of research interest in a field dubbed
“spintronics” of late, which could pave the way to exploit spin in addition to charge in semiconductor devices. The main challenge
for practical application of the DMS materials is the attainment of a Curie temperature at or preferably above room temperature
to be compatible with junction temperatures. Among the studies of transition-metal doped conventional III–V and II–VI semiconductors,
transition-metal-doped ZnO and GaN became the most extensively studied topical materials since the prediction by Dietl et al., based on mean field theory, as promising candidates to realize a diluted magnetic material with Curie temperature above
room temperature. The underlying assumptions, however, such as transition metal concentrations in excess of 5% and hole concentrations
of about 1020 cm−3, have not gotten as much attention. The particular predictions are predicated on the assumption that hole mediated exchange
interaction is responsible for magnetic ordering. Among the additional advantages of ZnO-and GaN-based DMSs are that they
can be readily incorporated in the existing semiconductor heterostructure systems, where a number of optical and electronic
devices have been realized, thus allowing the exploration of the underlying physics and applications based on previously unavailable
combinations of quantum structures and magnetism in semiconductors. This review focuses primarily on the recent progress in
the theoretical and experimental studies of ZnO- and GaN-based DMSs. One of the desirable outcomes is to obtain carrier mediated
magnetism, so that the magnetic properties can be manipulated by charge control, for example through external electrical voltage.
We shall first describe the basic theories forwarded for the mechanisms producing ferromagnetic behavior in DMS materials,
and then review the theoretical results dealing with ZnO and GaN. The rest of the review is devoted to the structural, optical,
and magnetic properties of ZnO- and GaN-based DMS materials reported in the literature. A critical review of the question
concerning the origin of ferromagnetism in diluted magnetic semiconductors is given. In a similar vein, limitations and problems
for identifying novel ferromagnetic DMS are briefly discussed, followed by challenges and a few examples of potential devices. 相似文献
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A new type of Mn-Cu-In-S diluted magnetic semiconductor quantum dots was synthesized and reported for the first time. The quantum dots, with no highly toxic elements, not only show the same classic diluted magnetic behavior as Mn-doped CdSe, but also exhibit tunable luminescent properties in a relatively large window from 542 to 648?nm. An absolute photoluminescence quantum yield up to 20% was obtained after the shell growth of ZnS. This kind of magnetic/luminescent bi-functional Mn-Cu-In-S/ZnS core/shell quantum dot might serve as promising nanoprobes for use in dual-mode optical and magnetic resonance imaging techniques. 相似文献
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J. D. Albrecht J. E. van Nostrand B. Claflin Y. Liu M. I. Nathan P. P. Ruden 《Journal of Superconductivity》2005,18(1):69-73
We present magnetometry and charge transport data for a GaMnN film with approximately 7% (atomic) Mn grown by molecular beam epitaxy. Measurements of magnetization vs. applied magnetic field show hysteresis consistent with the existence of ferromagnetism up to 300 K. Magnetization curves as a function of temperature indicate a phase transition near 170 K. Temperature-dependent Hall effect measurements show n-type characteristics with high carrier concentration and low mobility, which are both only weakly dependent on temperature. Piezoresistance measurements under hydrostatic pressure yield pressure coefficients that show little variation for temperatures of 77, 194, and 300 K. 相似文献