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研究了单层Ge-Sb-Te-O射频溅射薄膜在400nm~800nm区域的光学常数(N,K)和反射、透射光谱,发现适当的氧掺杂能增加退火前后反射率对比度,因此,可以通过氧掺杂改良Ge-Sb-Te相变材料的光存储性能. 相似文献
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《光学仪器》2003,(5)
美国得克萨斯技术大学的研究人员目前正在利用大带隙器件中的短周期晶格的结构特性制作基于Al Ga In N的太阳盲紫外光电探测器。这种紫外光电探测器具有较高的 AIN含量 ( AIN含量越高 ,器件可响应的波长就越短 ) ,其超晶格的周期为 1 .4nm,这可以形成 2 60 nm的有效带隙。这种简单的台面型二极管是在无表面钝化的蓝宝石上生长的 ,它有两层超晶格层 (一层 n型掺杂层 ,一层 p型掺杂层 ) ,每层超晶格层有 1 5 0对量子阱。平均 AIN含量为 0 .63。经观测 ,在接近零偏压时 ,其暗漏泄电流为 0 .2 p A~ 0 .3p A;对于直径为 2 80μm的器件来说… 相似文献
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为了获得高性能和低成本的氧化锌(ZnO)基紫外光探测器,使用Ga掺杂ZnO(ZnO∶Ga)作为光敏层,采用水热法合成了不同Ga掺杂浓度ZnO∶Ga微米棒,Ga与Zn的原子比分别为0%(未掺杂),0.5%,1%,2%和4%。使用X射线衍射仪(XRD)测试所有样品的晶体结构,发现它们都为六方纤锌矿结构的ZnO。采用扫描电子显微镜(SEM)观察它们的形貌,都呈现棒状结构。进一步,制备叉指图案氟掺杂的氧化锡(FTO)导电玻璃基底,将不同Ga掺杂浓度ZnO∶Ga微米棒分别涂覆在FTO上,得到5种简单结构的紫外光探测器,系统研究了它们的性能。结果表明:所有ZnO∶Ga微米棒紫外光探测器对365 nm紫外光表现出良好的响应。其中,1%Ga掺杂ZnO∶Ga微米棒紫外光探测器性能最佳,经计算,在365 nm波长处,它的响应度、增益和比探测率分别为13.13 A/W (5 V),44.63 (5 V),3.31×1012 Jones,响应时间和衰减时间分别为12.3 s和36.4 s。说明在ZnO微米棒中进行合适Ga掺杂能有效提高紫外光探测器的性能。该研究有助于基于ZnO∶Ga材料的... 相似文献
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本文研究具有不同碳含量的 Sb-5-2型高速钢的回火稳定性、残余奥氏体量、组织、碳化物类型、碳化物成分,基体成分、回火时碳化物的析出、强度和韧性等问题。 相似文献
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罗丹明6G在MPMMA中的光物理特性及激光性能 总被引:1,自引:0,他引:1
合成了激光染料罗丹明6G(R6G)掺杂的改性聚甲基丙稀酸甲酯(MPM-MA).研究了R6G掺杂MPMMA的吸收光谱、激发光谱及发射光谱。在Nd:YAG激光器532nm倍频激光作用下,看到了激光谐振。 相似文献
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采用传统熔体冷却法制备TiO2掺杂量(物质的量分数)为0~5.0%的CaO-Al2O3-SiO2(CAS)系玻璃,研究了TiO2掺杂量对该玻璃微观结构、热稳定性、弯曲强度的影响规律。结果表明:TiO2在CAS系玻璃网络中主要以[TiO5]单元的形式存在,随着TiO2掺杂量的增加,玻璃中的[TiO5]单元和Ti-O-Si键数量先增加后降低,玻璃网络中的桥氧数量先增多后减少,玻璃的光学带隙先增大后减小,且均在TiO2掺杂量为4.0%时达到最大值;随着TiO2掺杂量的增加,CAS系玻璃的热稳定性和弯曲强度均先提高后降低,当TiO2掺杂量为4%时综合性能最好,此时玻璃化转变温度、弯曲强度和光学带隙分别为798.24℃,95.58 MPa, 3.75 eV。 相似文献
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The phase transition phenomena of Ge2Sb2Te5 chalcogenides were investigated by in situ dynamic high-resolution transmission electron microscopy (HR-TEM) and electron energy loss spectroscopy (EELS). A 300kV field emission TEM and a 1250kV high voltage TEM were employed for the in situ heating experiments from 20 to 500 degrees C for undoped and 3wt% nitrogen-doped Ge2Sb2Te5 thin films deposited by DC sputtering. Crystallization of amorphous Ge2Sb2Te5 to its cubic structure phase started at 130 degrees C and then rapid crystal growth developed from cubic to hexagonal phase in the range of 130-350 degrees C; finally, the hexagonal crystals started to melt at 500 degrees C. For nitrogen-doped Ge2Sb2Te5, its crystallization from amorphous film occurred at higher temperature of ca. 200 degrees C, and the cubic and hexagonal phases were usually formed simultaneously without significant growth of crystals at further heating to 400 degrees C. EELS measurements showed that the electronic structures of Ge, Sb and Te stayed almost the same regardless of the amorphous, FCC and hexagonal phases. The nitrogen doped in Ge2Sb2Te5 was confirmed to exist as a nitride. Also, the doped nitrogen distributed homogeneously in both amorphous and crystalline phases. Localization of doped nitrogen was not found in the grain boundary of crystallized phases. The dynamic process of phase transition was enhanced by high-energy electron irradiation. Peeling of atomic layers in nitrogen-doped Ge2Sb2Te5 film was detected during heating assisted with electron beam irradiation. 相似文献
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利用Pb1-xGexTe材料的折射率异常性质改善红外光学薄膜的低温性能 总被引:1,自引:1,他引:0
红外薄膜干涉滤光片性能在低温下的变化是空间遥感系统中的一个关键性问题。经研究表明IV-VI族半导体PbTe和GeTe的赝二元合金Pb1-xGexTe在铁电相变点具有折射率异常—相应于铁电相变,Pb1-xGexTe薄膜呈现出最大折射率值。用Pb0.94Ge0.06Te材料代替PbTe材料,制作了一个红外薄膜干涉滤光片。测试结果表明:其中心波长漂移从0.48nm/K改进到0.23nm/K,在所测量的80K~300K的温度范围,用Pb0.94Ge0.06Te材料制作的滤光片的峰透过率高于用PbTe材料制作的滤光片约3%,从而极大地改善了光学薄膜器件在深低温环境下的稳定性和可靠性。 相似文献
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We have fabricated nanoscale recording marks on Ge(2)Sb(2)Te(5) (GST) films with conductive atomic force microscope (AFM). GST films were deposited on glass or polyimide film with thickness of 150-200nm by the rf-sputtering method. Through current-voltage (I-V) spectroscopy, good cantilevers for fabrication and characterization of nanoscale marks on GST were selected. A fresh and highly conductive tip showed voltage-switching characteristic in the I-V curve, where the threshold voltage was approximately 1.6V. Nanoscale dot and wire arrays of crystalline phases were successfully obtained by varying sample bias voltage from -10 to 10V. With highly conductive tips, nanowires having full-width at half-maximum of approximately 20nm could be fabricated, whereas nanowires could not be fabricated with bias voltage below -2V. The width of the nanoscale mark was increased by repetition of AFM lithography even with same applied voltage and lithography speed. For a thicker nanowire, the width measured in current-image (C-image) was observed to be approximately 2 times of that measured in topography-image (T-image). This result supports that current sensing provides an image of phase-changed GST area with higher resolution than topography sensing. 相似文献
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采用溶胶-凝胶浸渍提拉法(Sol-Gel Dip-Coating, SGDC)制备SnO_2纳米晶薄膜气敏传感器.较系统地研究了掺杂量、镀膜层次和热处理温度等制备工艺对薄膜表面形貌、晶粒大小及气敏性能的影响.研究结果表明:铟的最佳掺杂量为4at%,最佳镀膜层数为7层,最佳热处理温度为600 ℃.气敏传感器最佳工作温度为165 ℃,在此工作温度下,薄膜的灵敏度分别为26.3(137 ppm H_2S)和2.5(2.74 ppm H_2S),薄膜的响应恢复时间较短分别为8 s和22 s,对H_2S气体有较好的选择性. 相似文献
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By introducing electrical connections into the chamber of a scanning electron microscope (SEM) via its holder assembly, it has become feasible to in situ observe and electrically characterize electronic devices. The in situ SEM was applied to investigate electric-pulse-induced behavior of Ge(2)Sb(2)Te(5) in a lateral phase-change memory cell. Randomly distributed nuclei with sizes from 20 to 80 nm were initiated at a low voltage pulse. Initially, grain growth depended strongly on pulse amplitude at around 60.3 nm/V and then a weak pulse amplitude dependence was observed at around 13.5 nm/V. Device resistance during crystallization dropped by two to three orders of magnitude with two falling steps, which probably resulted from amorphous to face-centered-cubic and subsequently to hexagonal transitions, respectively. 相似文献
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The change from producing high strength low alloy (HSLA) steel sheet by conventional thick slab casting to producing it by direct charged thin slab casting causes a major change in the evolution of the precipitation. A key area of interest is the composition of the sub-10nm precipitates used to produce dispersion hardening. Carbon extraction replicas are frequently used to study precipitates in steels and other metals. When used with annular dark field imaging, this technique gives high contrast images of the precipitates while the thin carbon film adds little background or additional characteristic signals to either electron energy loss spectra or energy dispersive X-ray spectra. The method has the additional major advantage of removing the ferromagnetic matrix when studying HSLA steels. However, when the precipitates contain carbon, the C K-edge is dominated by the contribution from the amorphous carbon film. A plasma cleaner can be used to thin this carbon film to approximately 0.5 nm or less and then the contribution from the carbon in the precipitate can be separated from that in the carbon film using the electron energy loss near edge structure. A similar approach can be taken to separate the oxygen content of the precipitate from that of oxides formed from low-level impurities in the amorphous carbon during the plasma thinning process. In most cases, the precipitate studied here contained little or no oxygen even for the smallest sizes examined (approximately 4 nm). The precipitates contain mainly nitrogen with little carbon. For some compositions, the precipitates are clearly sub-stoichiometric. 相似文献
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为获得高性能紫外激光薄膜元件,急需研制紫外高反射吸收薄膜,实现吸收损耗的精确测量。本文采用离子束溅射技术,通过调控氧气流量实现了具有不同吸收的Ta_2O_5薄膜的制备。以Ta_2O_5薄膜作为高折射率材料,设计了355nm的紫外高反射吸收薄膜。采用离子束溅射沉积技术,在熔融石英基底上制备了355nm的吸收薄膜,对于A=5%的紫外吸收光谱,在355nm的透射率、反射率和吸收率分别为0.1%,95.0%和4.9%;对于A=12%的紫外吸收光谱,在355nm的透射率、反射率和吸收率分别为0.1%,87.4%和12.5%。实验结果表明,采用离子束溅射沉积技术,可以实现不同吸收率的355nm高反射吸收薄膜的制备,对于基于光热偏转测量技术的紫外光学薄膜弱吸收测量仪的定标具有重要的意义。 相似文献
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对结合激光辅助掺杂和毛化方法合成的光伏电池用Sb掺杂非晶硅薄膜进行了研究.首先,用阈值通量为460mJ/cm2的激光照射镀有200~300 nm厚Sb的非晶硅薄膜进行施主扩散.为激活施主,样品用230mJ/cm2的低激光通量再一次进行处理.进行施主激光扩散和活化时,激光光斑的重叠度达到光斑大小的90%,因此随后诱发了薄... 相似文献