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以SiH4为生长气源,利用VLS(气相-液相-固相)互反应生长机制,在RT-CVD生长设备上通过向(111)硅衬底表面引入Au,生长出长达数个微米而直径小于1μm的垂直于衬底表面的线状晶体。对生长出的线状晶体作了扫描电镜观察,并分析讨论了生长的异常现象。 相似文献
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等离子体辅助反应式脉冲激光熔蚀制备AIN薄膜的低温生长 总被引:3,自引:0,他引:3
使用等离子体辅助反应式脉冲激光溅射沉积薄膜的方法在Si(111)和Si(100)基片上已经成功地低温制备出AIN多晶膜。实验表明,当脉冲能量密度DE=1.0J·cm^-2,脉冲频率f=5Hz,氮气气压PN2=1.33×10^4Pa,基底温度tsub=200℃,放电电压V=650,基靶距离ds-T=4cm时薄膜的生长速度等于6nm/min。AIN薄膜的折射率为2.05,和基底的取向关系分别为:AIN 相似文献
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本介绍QUINDOS系统的几个应用问题及其解决方法。介绍了两项已开发的新功能,VAX机与PC机的联机通信了VMS软盘格式不兼容的问题;屏显图形功能实现了用PC机的VGA屏幕作为QUINDOS系统的一个图形终端,直接屏显各种测量结果图形。 相似文献
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用光致电流瞬态谱(PITS)方法研究了LECSI-GaAs原生单晶经常规退火和等时快速退火(RTA)深能级缺陷的变化。缺陷EL2(Ec-0.82eV)EL12(Ec-0.79eV)表现出类似的RTA特性,应属于EL2缺陷团簇;缺陷EL6(Ec-0.38eV),EL8(Ec-0.27eV)和EL9(Ec-0.24eV0亦具有相似的RTA特性,属EL6缺陷团簇。实验发现,在热退火中,EL2团簇缺陷密度 相似文献
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带有单纯疱疹病毒脱氧胸苷激酶基因(HSV-tk)的腺病毒结合ganciclovir(GCV)对分裂细胞有很强的杀伤作用。本文报道在感染复数(M.O.I,MultiPlicityofInfection)达到1000时对人体肺腺癌细胞A549的杀伤几乎达到回100%。四种人体肺癌细胞株(A549,LAX,SPC,SKY)对带HSV-tk的腺病毒(ADV/RSV-tK)的杀伤作用表现不同的敏感性。另外,Acyclovir(ACV)和GCV对感染了重组腺病毒ADV/RSV-tK的细胞都有一定杀伤作用,但杀伤效果有很大差别;就A549而言,GCV的杀伤作用比ACV高7—8倍。此外ADV/RSV-tk结合GCV杀伤肿瘤细胞时有“旁观者效应”,即感染了ADV/RSV-tk的细胞与未感染细胞混合后,后者也明显地遭到杀伤。 相似文献
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本文研究了MOCVD外延生长Ga1-xAlxAs1-6Sby半导体薄膜的生长条件与外延层组成的关系,并用人工神经网络法总结有关气固平衡规律。结果表明,用气相组成,载气流量和生长等影响外延层组成的主要参数作为人工神经网络的输入,以固相Ga1-xAlxAs1-ySby中的Al和Sb的含量x、y作为输出,训练的人工神经网络可以预报固相组成x、y,得到满意结果。 相似文献
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热压烧结制备了SiO2-AIN复合材料,研究了烧结温度、第二相颗粒AIN的引入量对AIN颗粒补强SiO2基复合材料介电性能的影响.结果说明:随着热压温度的提高,复合材料的介电常数增加,介电损耗减少;在一定的热压温度下,复合材料的介电常数和介电损耗随第二相颗粒AIN的引入量的增加而增加。1MHz时10vol%AIN-SiO2复合材料的介电常数和介电损耗分别为4.1和9.0x10-4。从复合材料的组成和结构角度对以上结果予以解释。 相似文献
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Ting XIE Min YE Xiaosheng FANG Zhi JIANG Li CHEN Mingguang KONG Yucheng WU Lide ZHANG 《材料科学技术学报》2008,24(4)
Aluminum nitride (AIN) nanowires, serrated nanoribbons, and nanoribbons were selectively obtained through a simple chloride assisted chemical vapor deposition process. The morphologies of the products could be controlled by adjusting the deposition position and the flux of the reactant gas. The morphologies and structures of the AIN products were investigated in detail. The formation mechanism of the as-prepared different morphologies of AIN one-dimensional (1D) nanostructures was discussed on the basis of the experimental results. 相似文献
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AIN nanowires with a hexagonal structure were synthesized using an improved arc-discharge method and their microstructures were characterized using a high-resolution transmission electron microscope. The synthesized AIN nanowires were of various shapes. Their diameters ranged from 20 to 110 nm and the lengths were up to 20μm. Most of the AIN nanowires were coated by an amorphous layer of aluminum oxide. Fabrication yield was about several grams. The growth mechanism was considered to be a vapor-liquid-solid process and an Al droplet formed on the top of as-grown AIN nanowire played a role of catalyst. 相似文献
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以AIN粉体为原料,加入适量的CaO-B2O3矿化剂,采用升华再结晶法制备AIN晶须.初步探讨了反应器及其合成温度对产物种类的影响,研究了晶须的结构特征及其生长机理.结果表明,初期的合成产物包括AIN晶柱、晶须和非晶AIN纤维,以VLS机制生长:后期产物为AIN晶须,表现为VS生长机制:XRD及TEM分析表明,晶须大多呈现沿{2110}、{101l}和{0001},l=0、1、2、3的晶面生长.多数晶须宏观生长轴向平行于这些晶面的法线,而部分晶须由于发生斜生长,导致宏观生长轴向与这些晶面的法线斜交. 相似文献
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Kirsch P Assouar MB Elmazria O Hakiki ME Mortet V Alnot P 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(7):1486-1491
In this work, we report on the fabrication results of surface acoustic wave (SAW) devices operating at frequencies up to 8 GHz. In previous work, we have shown that high acoustic velocities (9 to 12 km/s) are obtained from the layered AIN/diamond structure. The interdigital transducers (IDTs) made of aluminium with resolutions up to 250 nm were successfully patterned on AIN/diamond-layered structures with an adapted technological process. The uniformity and periodicity of IDTs were confirmed by field emission scanning electron microscopy and atomic force microscopy analyses. A highly oriented (002) piezoelectric aluminum nitride thin film was deposited on the nucleation side of the CVD diamond by magnetron sputtering technique. The X-ray diffraction effectuated on the AIN/diamond-layered structure exhibits high intensity peaks related to the (002) AIN and (111) diamond orientations. According to the calculated dispersion curves of velocity and the electromechanical coupling coefficient (K2), the AIN layer thickness was chosen in order to combine high velocity and high K2. Experimental data extracted from the fabricated SAW devices match with theoretical values quite well. 相似文献
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Mousavi SH Gharavi MA Haratizadeh H Kitai A de Oliveira PW 《Journal of nanoscience and nanotechnology》2011,11(9):8284-8288
Aluminum nitride (AIN) is a direct bandgap semiconductor with a bandgap about 6.1 eV at room temperature, the largest among semiconductors. This paper emphasizes experimental results of the growth and optical properties of AIN nanostructures by direct nitridation. The nitridation process was performed by chemical vapor deposition method with nitrogen (N2) gas flow. AIN nanostructures were analyzed by scanning electron microscope (SEM) equipped with energy-dispersive X-ray (EDX) spectroscope and photoluminescence (PL) spectroscopy. AIN nanowires with different widths from ultrathin to thick were synthesized with this method. All of the samples had high purity without presence of any other material in EDX spectrum. The PL spectra were obtained by a 325-nm helium-cadmium (He-Cd) laser as the excitation source showing high-intensity light emitting visible wavelengths for these structures at room temperature. 相似文献
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Yoon SW Seo JH Chae KH Park JK Song JH Jayaram V Lee KB Seong TY Hoon-Kwon Ahn JP 《Journal of nanoscience and nanotechnology》2012,12(2):1476-1479
AIN/CrN multilayer hard coatings with various bilayer thicknesses were fabricated by a reactive sputtering process. The microstructural and mechanical characterizations of multilayer coatings were investigated through transmission electron microscope (TEM) observations and the hardness measurements by nano indentation. In particular, the variation of chemical bonding states of the bilayer nitrides was elucidated by near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Many broken nitrogen bonds were formed by decreasing the bilayer thickness of AIN/CrN multilayer coatings. Existence of optimum AIN/CrN multilayer coatings thickness for maximum hardness could be explained by the competition of softening by the formation of broken nitrogen bonds and strengthening induced by decreasing bilayer thickness. 相似文献