共查询到20条相似文献,搜索用时 156 毫秒
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利用低能双离子束外延技术 ,在 4 0 0℃条件下生长样品 (Ga,Mn,As) / Ga As.样品光致发光谱出现三个峰 ,即1.5 0 4 2 e V处的 Ga As激子峰、1.4 875 e V处的弱碳峰和低能侧的一宽发光带 .宽发光带的中心位置在 1.35 e V附近 ,半宽约 0 .1e V.在 84 0℃条件下对样品进行退火处理 ,退火后的谱结构类似退火前 ,但激子峰和碳杂质峰的峰位分别移至 1.5 0 6 5 e V和 1.4 894 e V,同时低能侧的宽发光带的强度大大增加 .这一宽发射带的来源还不清楚 ,原因可能是体内杂质和缺陷形成杂质带 ,生成 Mn2 As新相 ,Mn占 Ga位或形成 Ga Mn As合金 相似文献
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7月9日,《物理评论快报》(Phys.Rev.Lett.111,027203 2013)报道了中科院半导体研究所半导体超晶格国家重点实验室赵建华研究组及合作者在(Ga,Mn)As/Co2FeAl双层膜铁磁界面耦合和磁邻近效应方面取得的最新研究成果。(Ga,Mn)As兼具铁磁体和半导体的性质,过去十多年里受到了高度关 相似文献
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在国产分子束外延设备的基础上 ,利用新型三温区阀控裂解源炉 ,对 In P及 In Ga As P材料的全固源分子束外延 (SSMBE)生长进行了研究。生长了高质量的 In P外延层 ,表面缺陷密度为 65cm- 2 ,非故意掺杂电子浓度约为 1× 1 0 16cm- 3.In P外延层的表面形貌、生长速率及 p型掺杂特性与生长温度密切相关 .研究了 In Ga As P外延材料的组分特性 ,发现在一定温度范围内生长温度对 族原子的吸附系数有较大影响 .最后得到了晶格匹配的 In0 .56Ga0 .4 4 As0 .94 P0 .0 6材料 ,低温光致发光谱峰位于 1 50 7nm,FWHM为 9.8me V. 相似文献
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借助超薄低温InP缓冲层,在GaAs衬底上生长出了高质量的InP外延层,在InP外延层中插入了15周期In0.93Ga0.07P/InP应变层超晶格(SLS),进一步阻断了失配位错穿透到晶体表面,提高了外延层的晶体质量,这样2.5 μm厚InP外延层的双晶X射线衍射(DCXRD)ω扫描半高全宽(FWHM)值降低至219 arcsec,该InP外延层的室温光荧光(PL)谱线宽度仅为42 meV.在此基础上,只利用超薄低温InP缓冲层技术就在半绝缘GaAs衬底上成功地制备出了长波长异变In0.53Ga0.47As PIN光电探测器,器件的台面面积为50 μm×50 μm,In0.53Ga0.47As吸收层厚度为300 nm,在3 V反偏压下器件的3 dB带宽达到了6 GHz,在1 550 nm波长处器件的响应度达到了0.12 A/W,对应的外量子效率为9.6%. 相似文献
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分子束外延生长高应变单量子阱激光器 总被引:1,自引:1,他引:0
采用分子束外延方法研究了高应变 In Ga As/Ga As量子阱的生长技术 .将 In Ga As/Ga As量子阱的室温光致发光波长拓展至 116 0 nm,其光致发光峰半峰宽只有 2 2 me V.研制出 112 0 nm室温连续工作的 In Ga As/Ga As单量子阱激光器 .对于 10 0 μm条宽和 80 0 μm腔长的激光器 ,最大线性输出功率达到 2 0 0 m W,斜率效率达到 0 .84m W/m A,最低阈值电流密度为 45 0 A/cm2 ,特征温度达到 90 K. 相似文献
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Moon-Ho Ham Min-Chang Jeong Woo-Young Lee Jae-Min Myoung Jeung-Mi Lee Joon-Yeon Chang Suk-Hee Han 《Journal of Electronic Materials》2004,33(2):114-117
We present the magnetic and magnetotransport properties of epitaxial (Ga,Mn)N films with nominal Mn concentration (x=0.1–0.73%)
grown by plasma-enhanced molecular beam epitaxy (PEMBE). X-ray diffraction (XRD) reveals that (Ga,Mn)N has the single-phase
wurtzite structure without secondary phases. The epitaxial (Ga,Mn)N films were found to exhibit n-type conductivity, ferromagnetic
ordering with Curie temperature in the range 550–700 K, and in-plane magnetic anisotropy. The negative magnetoresistance (MR)
was observed at temperatures below 50 K and was found to gradually increase with decreasing temperature. 相似文献
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I. L. Kalentyeva O. V. Vikhrova Yu. A. Danilov B. N. Zvonkov A. V. Kudrin M. N. Drozdov 《Semiconductors》2016,50(11):1469-1474
The effects of isochronal thermal annealing (at 325–725°C) on the radiative properties of InGaAs/GaAs nanoheterostructures containing a low-temperature GaAs layer δ-doped with Mn grown by laser deposition are studied. A decrease in the photoluminescence intensity and increase in the ground transition energy are observed upon thermal impact for quantum wells located near the low-temperature GaAs layer. The distribution of Mn atoms in the initial and annealed structures is obtained by secondary-ion mass spectrometry. A qualitative model of the observed effects of thermal annealing on the radiative properties of the structures is discussed; this model takes into account two main processes: diffusion of point defects (primarily gallium vacancies) from the GaAs coating layer deep into the structure and Mn diffusion in both directions by the dissociation mechanism. Magnetization studies show that, as a result of thermal annealing, an increase in the proportion of the ferromagnetic phase at room temperature (presumably, MnAs clusters) in the low-temperature GaAs coating layer takes place. 相似文献
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Yuanqi Huang Zhengwei Chen Xiao Zhang Xiaolong Wang Yusong Zhi Zhenping Wu Weihua Tang 《半导体学报》2018,39(5):16-20
High quality epitaxial single phase (Ga0.96Mn0.04)2O3 and Ga2O3 thin films have been prepared on sapphire substrates by using laser molecular beam epitaxy (L-MBE).X-ray diffraction results indicate that the thin films have the monoclinic structure with a (-201) preferable orientation.Room temperature (RT) ferromagnetism appears and the magnetic properties of β-(Ga0.96Mn0.04)2O3 thin film are enhanced compared with our previous works.Experiments as well as the first principle method are used to explain the role of Mn dopant on the structure and magnetic properties of the thin films.The ferromagnetic properties are explained based on the concentration of transition element and the defects in the thin films. 相似文献
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A. M. Jakob M. Hennes M. Müller D. Spemann S. G. Mayr 《Advanced functional materials》2013,23(37):4694-4702
Micromagnetic structure evolution in Ni‐Mn‐Ga ferromagnetic shape memory thin films is investigated by means of temperature dependent magnetic force microscopy (TD‐MFM). The center of interest is the magnetic properties of epitaxial Ni‐Mn‐Ga thin films on MgO substrates across thermally induced phase transitions. Experimental results are discussed within the framework of competing magnetic interactions arising in stressed thin ferromagnetic films. Measurements on 14M martensite specimens are supplemented by three‐dimensional micromagnetic simulations. Corresponding calculated MFM micrographs are compared to experimental data. The influence of twin variant dimension and orientation on micromagnetic domain formation and wall structure is depicted from a theoretical point of view. A micromagnetic model system of partial flux closure is proposed and calculated analytically to estimate a stress induced magneto crystalline anisotropy constant in austenite Ni‐Mn‐Ga. 相似文献
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Sanghoon Lee Sunjae Chung Hakjoon Lee Xinyu Liu M. Dobrowolska J. K. Furdyna 《半导体学报》2019,40(8):081503-081503-8
This paper describes interlayer exchange coupling (IEC) phenomena in ferromagnetic multilayer structures, focusing on the unique IEC features observed in ferromagnetic semiconductor (Ga,Mn)As-based systems. The dependence of IEC on the structural parameters, such as non-magnetic spacer thickness, number of magnetic layers, and carrier density in the systems has been investigated by using magnetotransport measurements. The samples in the series show both a typical anisotropic magnetoresistance (AMR) and giant magnetoresistance (GMR)-like effects indicating realization of both ferromagnetic (FM) and antiferromagnetic (AFM) IEC in (Ga,Mn)As-based multilayer structures. The results revealed that the presence of carriers in the non-magnetic spacer is an important factor to realize AFM IEC in this system. The studies further reveal that the IEC occurs over a much longer distance than predicted by current theories, strongly suggesting that the IEC in (Ga,Mn)As-based multilayers is a long-range interaction. Due to the long-range nature of IEC in the (Ga,Mn)As-based systems, the next nearest neighbor (NNN) IEC cannot be ignored and results in multi-step transitions during magnetization reversal that correspond to diverse spin configurations in the system. The strength of NNN IEC was experimentally determined by measuring minor loops that correspond to magnetization flips in specific (Ga,Mn)As layer in the multilayer system. 相似文献
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The paper demonstrates the operation of several devices based on tunneling anisotropic magnetoresistance. This effect, which originates from the interplay between the magnetic and transport properties in magnetic materials with strong spin-orbit coupling such as the ferromagnetic semiconductor (Ga,Mn)As, leads to a dependence of the tunneling resistance of devices with respect to the direction of the magnetization in the (Ga,Mn)As layer. We show that such devices can be operated as either information storage elements or sensors. It was also demonstrated that they can be used in either volatile or nonvolatile mode and that they provide either two-state or multiple state devices in either of these modes. Lastly, we present experimental evidence that they can be coupled to traditional ferromagnetic materials to still further enhance the variety of possible device functionalities 相似文献
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J. S. Lee Z. G. Khim Y. D. Park D. P. Norton N. A. Theodoropoulou A. F. Hebard J. D. Budai L. A. Boatner S. J. Pearton R. G. Wilson 《Solid-state electronics》2003,47(12):2225
Implantation of Co or Mn into single-crystal BaTiO3(K), SrTiO3 or KTaO3(Ca), followed by annealing at 700 °C, produced ferromagnetic behavior over a broad range of transition metal concentrations. For BaTiO3, both Co and Mn implantation produced magnetic ordering temperatures near 300 K with coercivities 70 Oe. The M–T plots showed either a near-linear decrease of magnetization with increasing temperature for Co and a non-Brillouin shaped curve for Mn. No secondary phases were detected by high-resolution X-ray diffraction. The same basic trends were observed for both SrTiO3 and KTaO3, with the exception that at high Mn concentrations (5 at.%) the SrTiO3 was no longer ferromagnetic. Our results are consistent with recent reports of room temperature ferromagnetism in other perovskite systems (e.g. LaBaMnO3) and theoretical predictions for transition metal doping of BaTiO3 [Nakayama et al., Jap. J. Appl. Phys. 40 (2001) L1355]. 相似文献
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A. D. Bouravleuv G. E. Cirlin V. V. Romanov N. T. Bagraev E. S. Brilinskaya N. A. Lebedeva S. V. Novikov H. Lipsanen V. G. Dubrovskii 《Semiconductors》2012,46(2):179-183
The molecular-beam epitaxy technique is used to synthesize arrays of (Ga,Mn)As nanowire crystals on a GaAs (111)B surface
in the growth-temperature range 480–680°C. It is established that the formation of (Ga,Mn)As nanowires can be described in
the context of a vapor-liquid-crystal mechanism. It is shown that the growth of (Ga,Mn)As nanowires must occur in conditions
stabilized with respect to Ga. It is found that the field and temperature dependences of the static magnetic susceptibility
for samples produced at the temperature 660°C exhibit paramagnetic behavior. 相似文献
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W. Limmer M. Glunk J. Daeubler T. Hummel W. Schoch C. Bihler H. Huebl M.S. Brandt S.T.B. Goennenwein R. Sauer 《Microelectronics Journal》2006,37(12):1490-1492
The magnetic anisotropy of a 40-nm-thick (Ga,Mn)As film with 5% Mn grown on GaAs(1 1 3)A is studied by means of magnetotransport and ferromagnetic resonance (FMR) spectroscopy. In addition to the cubic and a weak uniaxial in-plane anisotropy, two uniaxial out-of-plane contributions along [1 1 3] and [0 0 1] are found. Using the anisotropy parameters determined from FMR, the longitudinal and transverse resistivities measured as a function of magnetic field orientation and strength are well modelled within the framework of a single ferromagnetic domain. In particular, the low-field data which are strongly affected by sudden jumps of the magnetization are well reproduced. 相似文献