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从理论和实验上对Fe/MnPd薄膜的交换偏置效应、各向异性和矫顽力的增加作了系统的研究.研究表明,在FM/AF结构中,FM和AF的交换耦合作用会诱导系统产生高阶各向异性,在Fe/MnPd结构中获得的单轴和立方各向异性的大小同单轴各向异性与铁磁层的厚度成反比关系一样.同时,铁磁层(FM)和反铁磁层(AF)的交换耦合作用诱导而产生的高阶各向异性的存在是使系统矫顽力增加的重要原因.
关键词: 相似文献
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金刚石膜/多孔硅复合材料的性能表征 总被引:4,自引:2,他引:2
提出了一种新颖的多孔硅表面钝化技术,即采用微波等离子体辅助的化学气相沉积(MPCVD)方法在多孔硅上沉积金刚石薄膜。采用原子力显微镜(AFM)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)、拉曼光 谱仪和荧光分光度计对多孔硅及金刚石膜的表面形貌、结构和发光特性进行了表征。结果表明采用微波等离子体化学气相沉积法可在多孔硅基片上形成均匀、致密、性能稳定且对可见光具有全透性的金刚石膜。金刚石膜与多孔硅的复合,大大稳定了多孔硅的发光波长和强度,同时增强了多孔硅的机械强度。 相似文献
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多孔硅——一种新形态的硅材料 总被引:3,自引:0,他引:3
多孔硅(porous Silicon)是指通过对氢氟酸溶液中的晶体硅片进行阳极氧化,在硅衬底上形成的多孔态的硅材料.本文介绍了多孔硅的形成规律和结构形貌,并对其光学性质和形成机制仆行了简要的评介,最后以多孔硅在大规模集成电路中的应用为主讨论了它的技术应用. 相似文献
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在多孔硅衬底上用射频溅射法沉积了非晶的SiC:Tb薄膜. 对样品在N2中进行了不同温度的退火处理. 用傅里叶红外变换谱分析了样品的结构.用荧光光谱仪测试了样品的光致发光,在紫外、可见光区域观测到了强的发光峰.发现随着衬底加热温度和样品退火温度的变化,发光峰有明显的强度变化和微弱的蓝移现象.分析了产生这种现象的机理,得出了紫外区域的发光峰是由于氧缺乏中心引起的,而可见区的发光是由于Tb离子产生的.
关键词:
碳化硅
光致发光
氧缺乏中心
多孔硅 相似文献
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V. V. Filippov V. P. Bondarenko P. P. Pershukevich V. S. Khomenko 《Journal of Applied Spectroscopy》1997,64(4):514-517
We obtained porous silicon films modified at room temperature by an Eu3+-containing polymer complex. The most intense photoluminescence of Eu3+ implanted in the porous silicon was observed at the wavelengths of 611, 618, 691, and 704 nm. In this case, the intensity
of the intrinsic photoluminescence of strongly irradiated specimens of porous silicon decreased, while the intensity of weakly
emitting films multiply increased. An investigation of the photoexcitation spectra made it possible to establish the effect
of Eu3+-containing complexes on the mechanism underlying the excitation of photoluminescence of porous silicon.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 4, pp. 499–501, July–August, 1997. 相似文献
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Porous silicon (PS) prepared from n-type Si crystal is proposed as a new material for the fabrication of sensitive substrates for surface-enhanced Raman scattering (SERS). The formation procedure for nanostructured silver films on the surface of PS was optimized. Maximum of SERS enhancement for rhodamine 6G probing molecule is observed for samples obtained by the immersion plating from the water solution of AgNO3 with the 10 mM concentration during 5 min. The dependence of morphological parameters of PS and corresponding silvered surfaces on the anodization current density has been studied. It is shown that the most SERS activities possess substrates produced from PS with lower porosity. The optimum of the PS layer thickness for high Raman signal is about 5 μm. The detection limit for rhodamine 6G adsorbed on Ag-coated PS from the 100 pM solution is established to be comparable with that for p-type PS-based substrates. Thus, the n-type porous silicon is suitable material for the preparation of sensitive SERS-active substrates. 相似文献
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Zhihao Yue Honglie ShenHong Cai Hongjie LvBin Liu 《Physica B: Condensed Matter》2012,407(12):2278-2281
In this paper, epitaxial silicon films were grown on annealed double layer porous silicon by LPCVD. The evolvement of the double layer porous silicon before and after thermal annealing was investigated by scanning electron microscope. X-ray diffraction and Raman spectroscopy were used to investigate the structural properties of the epitaxial silicon thin films grown at different temperature and different pressure. The results show that the surface of the low-porosity layer becomes smooth and there are just few silicon-bridges connecting the porous layer and the substrate wafer. The qualities of the epitaxial silicon thin films become better along with increasing deposition temperature. All of the Raman peaks of silicon films with different deposition pressure are situated at 521 cm−1 under the deposition temperature of 1100 °C, and the Raman intensity of the silicon film deposited at 100 Pa is much closer to that of the monocrystalline silicon wafer. The epitaxial silicon films are all (4 0 0)-oriented and (4 0 0) peak of silicon film deposited at 100 Pa is more symmetric. 相似文献
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A.P. Pardo Gonzalez H.G. Castro-LoraL.D. López-Carreño H.M. MartínezN.J. Torres Salcedo 《Journal of Physics and Chemistry of Solids》2014
ZnSe thin films were deposited onto Corning glass and silicon substrates using thermal evaporation. The samples were prepared at different substrate temperatures. The thin films’ surface chemical composition was determined through Auger electron spectroscopy (AES). AES signals corresponding to Zn and Se were only detected in AES spectra. The samples’ crystallographic structure was studied through X-ray diffraction. The material crystallised in the cubic structure with preferential orientation (111). Optical properties of the ZnSe films were studied over two energy ranges via electron energy loss spectroscopy (10–90 eV) and spectral transmittance measurements (0.4–4 eV). In both cases, the spectral variation of the refractive index and the absorption coefficient were determined by fitting the experimental results with well-established theoretical models. Experimental values for the material’s gap were also found, and photoconductivity (PC) measurements were carried out. Transitions between bands, usually labelled ΓV8 → ΓC6 and ΓV7 → ΓC6, were found in the optical and PC responses. A wide spectral photoconductive response between 300 and 850 nm was found in the ZnSe/Si samples prepared at 250 °C substrate temperature. 相似文献
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Yasuhiro Yamada Kenichi Tanabe Naoki Nishida Yoshio Kobayashi 《Hyperfine Interactions》2016,237(1):105
Iron films were deposited on porous alumina substrates using an arc plasma gun. The pore sizes (120 – 250 nm) of the substrates were controlled by changing the temperature during the anodic oxidation of aluminum plates. Iron atoms penetrated into pores with diameters of less than 160 nm, and were stabilized by forming γ-Fe, whereas α-Fe was produced as a flat plane covering the pores. For porous alumina substrates with pore sizes larger than 200 nm, the deposited iron films contained many defects and the resulting α-Fe had smaller hyperfine magnetic fields. In addition, only a very small amount of γ-Fe was obtained. It was demonstrated that the composition and structure of an iron film can be affected by the surface morphology of the porous alumina substrate on which the film is grown. 相似文献
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V. V. Filippov V. V. Kuznetsova V. S. Khomenko P. P. Pershukevich V. P. Bondarenko 《Journal of Applied Spectroscopy》1999,66(3):464-469
Er3+ and Yb3+ ions are introduced into porous silicon films, stabilized by oxidation in an oxygen plasma, in the form of a gadolinium oxychloride-based
luminophor by means of thermal diffusion. An investigation is made of the luminescence and photoexcitation spectra of samples
with Er3+ (10 and 30 wt.%), Yb3+ (10 wt.%), and Er3, Yb3++ (10 wt.% each). It is shown that the intense IR luminescence (1.00 and 1.54 μm) is caused by cross-relaxation effects. The
most effective excitation of the luminescence has been observed in the UV absorption band of the porous silicon.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 428–433, May–June, 1999. 相似文献
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利用电化学腐蚀方法制备了n型有序多孔硅, 并以此为基底用直流磁控溅射法在其表面溅射不同厚度的氧化钨薄膜. 利用X射线和扫描电子显微镜表征了材料的成分和结构, 结果表明, 多孔硅的孔呈柱形有序分布, 溅射10 min的WO3薄膜是多晶结构, 比较松散地覆盖在整个多孔硅的表面. 分别测试了多孔硅和多孔硅基氧化钨在室温条件下对二氧化氮的气敏性能, 结果表明, 相对于多孔硅, 多孔硅基氧化钨薄膜对二氧化氮的气敏性能显著提高. 对多孔硅基氧化钨复合结构的气敏机理分析认为, 多孔硅和氧化钨薄膜复合形成的异质结对良好的气敏性能起到主要作用, 氧化钨薄膜表面出现了反型层引起了气敏响应时电阻的异常变化.
关键词:
有序多孔硅
氧化钨薄膜
二氧化氮
室温气敏性能 相似文献
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F. Kezzoula A. Hammouda M. KechouaneP. Simon S.E.H. AbaidiaA. Keffous R. CherfiH. Menari A. Manseri 《Applied Surface Science》2011,257(23):9689-9693
Amorphous silicon (a-Si) and hydrogenated amorphous silicon (a-Si:H) films were deposited by DC magnetron sputtering technique with argon and hydrogen plasma mixture on Al deposited by thermal evaporation on glass substrates. The a-Si/Al and a-Si:H/Al thin films were annealed at different temperatures ranging from 250 to 550 °C during 4 h in vacuum-sealed bulb. The effects of annealing temperature on optical, structural and morphological properties of as-grown as well as the vacuum-annealed a-Si/Al and a-Si:H/Al thin films are presented in this contribution. The averaged transmittance of a-Si:H/Al film increases upon increasing the annealing temperature. XRD measurements clearly evidence that crystallization is initiated at 450 °C. The number and intensity of diffraction peaks appearing in the diffraction patterns are more important in a-Si:H/Al than that in a-Si/Al layers. Results show that a-Si:H films deposited on Al/glass crystallize above 450 °C and present better crystallization than the a-Si layers. The presence of hydrogen induces an improvement of structural properties of poly-Si prepared by aluminium-induced crystallization (AIC). 相似文献
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Y. A. Pusep A. D. Rodrigues L. J. Borrero‐Gonzlez L. N. Acquaroli R. Urteaga R. D. Arce R. R. Koropecki M. Tirado D. Comedi 《Journal of Raman spectroscopy : JRS》2011,42(6):1405-1407
Unexpectedly, the Fano resonance caused by the interference of continuum electron excitations with the longitudinal optical (LO) phonons was observed in random porous Si by Raman scattering. The analysis of the experimental data shows that the electron states trapped at the Si SiO2 interface dominate in the observed Raman scattering. The gap energy associated with the interface states was determined. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献