共查询到20条相似文献,搜索用时 468 毫秒
1.
掺半花菁二氧化硅薄膜二阶光学非线性与薄膜结构的动态变化关系 总被引:1,自引:1,他引:0
用溶胶-凝胶技术制备的掺入半花菁染料的二氧化硅薄膜在不加电场极化条件下,由半花菁分子的自取向导致光学二次谐波产生,定量测得厚度为50nm薄膜的二阶非线性系数x(2)为6.6pm/V,着重研究了薄膜稳定前的溶剂挥发过程中,膜结构的变化以及相应二阶光学非线性的变化,在成膜后的四个小时中,质子化半花菁逐步转化为单体和聚集体态,同时,光学二次谐波信号也不断增大,还观察到在这一过程中出现了单体和聚集态半花菁 相似文献
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采用实时光学二次谐波产生(SHG)测量方法,以两亲性分子半花菁为掺杂探针分子,对溶胶-凝胶技术制备的玻璃薄膜的凝胶干燥的动态过程进行了研究.结合紫外—可见吸收光谱的测量,发现:因两亲性分子在膜中的自取向性可诱导出二阶光学非线性,溶胶-凝胶技术制备的有机/无机复合膜的凝胶干燥过程可通过薄膜SHG强度的变化半定量地反映.凝胶干燥收缩导致有序掺杂分子数减少,膜片的光学非线性减弱.该过程随薄膜处理温度的升高而急剧缩短;另外,有机分子在膜中的聚集程度随膜片处理温度的增加而很快减少.
关键词: 相似文献
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利用稳态荧光谱和时间分辨荧光技术研究了温度对半花菁Langmuir-Blodgett(LB)多层膜光致荧光特性的影响.半花菁分子在半花菁/花生酸、半花菁/花生酸镉交替及纯半花菁Z-型LB多层膜中均形成了H-聚集体,加热能使聚集体部分离解.由于Z-型膜中没有花生酸或花生酸镉的屏蔽,分子间具有较强的偶极相互作用,加热使聚集体的离解的程度较小.镉离子的加入对半花菁LB多层膜的稳态荧光谱也有一定的影响. 相似文献
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用光学线性和非线性方法研究了Y型半花菁/花生酸交替LB多层膜的光致光学各向异性。在纳秒紫外偏振脉冲激光照射下,LB多层膜中半花菁分子发色团长轴向紫外光偏振方向重新取向。加热可以使LB多层膜平面内各向异性消失及H-聚集体分解。 相似文献
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对室温下染料单分子进行了偶极取向和偶极再取向动力学的实验研究.利用共焦扫描显微镜光学系统与荧光偏振探测分析相结合的方法分别测量了聚合体薄膜中的单分子和无聚合体薄膜的单分子偶极方向变化特性,经采样统计测量镶嵌于聚合体薄膜中的单分子发生偶极再取向的概率约为5%—9%,无聚合体薄膜的单分子发生偶极再取向的概率约为26%.通过测量单分子荧光的偏振度轨迹曲线发现,偶极再取向存在着在多个偏振态之间的量子化跳跃行为.
关键词:
单分子
偶极取向
再取向
量子化跳跃 相似文献
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通过射频磁控溅射技术在GaAs,Au/GaAs,Si和玻璃基片上成功制备了ZnO多晶薄膜,利用X射线衍射对ZnO薄膜的取向、结晶性进行了表征,结果表明ZnO薄膜呈完全c轴取向,Au缓冲层可以有效地改善ZnO薄膜的晶体质量,X射线摇摆曲线结果表明ZnO(002)衍射峰的半高宽仅为2.41°,同时发现Au缓冲层的结晶质量对ZnO薄膜的c轴取向度有很大影响,通过扫描电子显微镜对ZnO/GaAs和ZnO/Au/GaAs薄膜的表面形貌进行了观测,利用网络分析仪对IDT/ZnO/GaAs薄膜的声表面波特性进行了测量.
关键词:
ZnO薄膜
X射线衍射
声表面波 相似文献
10.
利用激光脉冲沉积(PLD)技术在(302)γ-LiAlO2衬底上成功生长了非极性的a面(1120) ZnO薄膜. 衬底温度为350℃时,薄膜是混合取向(a向和c向),以c面ZnO为主,且晶粒尺寸分布很宽;提高温度达500℃,薄膜变为单一的(1120)取向,摇摆曲线半高宽0.65°,晶粒尺寸分布趋窄,利用偏振透射谱可以明显看出其面内的各向异性. 衬底温度650℃下制备的样品晶粒继续长大,虽然摇摆曲线半高宽变大,但光致发光谱(PL)带边发射峰半高宽仅为105meV,比在350℃,500℃下制备的样品小1/5.
关键词:
非极性ZnO
2')" href="#">γ-LiAlO2
PLD
透射谱 相似文献
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T. C. He C. S. Wang X. Pan C. Z. Zhang G. Y. Lu 《Applied physics. B, Lasers and optics》2009,94(4):653-659
A novel azobenzene-containing fluorinated polyimide was synthesized. The nonlinear optical property and photoinduced birefringence
of a polyimide thin film were investigated. Large third-order nonlinear refraction (n
2=−4.49×10−11 cm2/W) was observed in the polyimide thin film by carrying out Z-scan measurement. The polyimide thin film exhibited larger nonlinear
refraction than that of a mono-azo dye doped PMMA thin film (n
2=−1.63×10−12 cm2/W). The photoinduced birefringence of the polyimide thin film (▵
n∼10−2) under different pump intensities was investigated; it was much larger than that of the mono-azo dye doped PMMA thin film
(▵
n∼10−3). Moreover, the time constants for birefringence growth and relaxation processes were determined. 相似文献
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利用直流磁控共溅射方法制备了GaN:Er薄膜.X射线衍射结果显示薄膜为纳米多晶结构,根据谢乐公式,计算得到了GaN薄膜晶粒的平均大小为58nm;透射电子显微镜结果显示为非晶基质中镶嵌了GaN纳米颗粒,尺寸在6—8nm之间;紫外可见谱结果表明在500—700nm的可见光范围内,薄膜的平均透过率大于80%,在紫外可见谱基础上,利用Tauc公式计算得到了纳米晶GaN薄膜的光学带隙为322eV;最后,测量了GaN:Er薄膜的室温光致发光谱,获得了Er3+离子在554nm处的强烈绿光发射.
关键词:
纳米晶GaN薄膜
3+掺杂')" href="#">Er3+掺杂
光学带隙
光致发光 相似文献
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Using the lyotropic liquid crystalline templating strategy, the nanostructured platinum film was electrochemically deposited on the α-Al2O3 supported dense palladium membrane. The XRD and TEM results of the Pt film revealed a hexagonal array of cylindrical pores with a uniform pore diameter of ca. 3.8 nm and a pore-to-pore separation of ca. 7.6 nm. The structure parameters of the Pt film were almost the same as those of the hexagonal liquid crystalline template. Based on SEM observations, the Pt film was featureless, smooth, and tightly adherent to the dense Pd membrane. The specific surface area of the Pt film, measured by using cyclic voltammetry, was ca. 13.8 m2 g−1, which was in accord with the theoretical value of 14.5 m2 g−1 for a perfect hexagonal nanostructure with the same structure parameters. By combining the dense Pd membrane for selective permeation to hydrogen with the Pt film of high specific surface area for catalysis, the as-synthesized two-layer film will be a promising catalytic membrane to intensify hydrogen-related reaction processes. 相似文献
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Field-electron emission from polyimide-ablated films 总被引:1,自引:0,他引:1
H. Ma L. Zhang N. Yao Z. Bi B. Zhang H. Hu 《Applied Physics A: Materials Science & Processing》2000,71(3):281-284
Polyimide-ablated film was deposited by using pulsed laser ablation of a polyimide target, and field-electron emission from
the film was observed for the first time. The turn-on field of the polyimide-ablated film is 12 V/μm. The current density
is 0.725 mA/cm2, and the emission sites density is on the order of 106/cm2 at the applied field of 24 V/μm. The field-electron emission measurements indicate that this kind of film could be a new
cold cathode material. It is suggested that the graphite-like clusters contained in the film play an important role in the
field-electron emission.
Received: 2 February 2000 / Accepted: 13 March 2000 / Published online: 9 August 2000 相似文献
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N. Yu. Svechnikov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(1):21-29
The 2D-photoemission image of the beam spot was obtained for the first time for the W5+ oxidation state on the preliminary irradiated WO3 − x
thin film surface, created by scanning of the SR beam over the film surface. The W5+ beam profile intensity was found to spread up to a distance of 3.2 μm for an amorphous film and 5.5 μm for a polycrystalline
film, it exceeds considerably the beam spot size. The image saturation dose was reached faster for a polycrystalline film.
Among the possible mechanisms explaining this phenomenon, for the case of an almost unchangeable O2s state under irradiation, a choice was made in favor of a photon-generated charge diffusion due to low-energy secondary electrons
from photoemission, which produce the “coloration” effect, e− + W6+ (W5+) W5+ → W5+(W4+). The O512-eV Auger peak was found to degrade at the distance of 1.5–2 mm outside the beam spot under long-time electron
beam irradiation, which is attributed to electron-stimulated oxygen desorption and outdiffusion. 相似文献
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A thin film of dilute Fe (0.008)-doped Sb0.95Se0.05 alloy was grown on silicon substrate using the thermal evaporation technique. This film was irradiated with swift heavy ions (SHIs) Ag+15 having 200?MeV energy at ion fluences of 1?×?1012 and 5?×?1012 ions per cm2, respectively. The thickness of the thin film was ~500?nm. We study the effect of irradiation on structural, electrical, surface morphology and magnetic properties of this film using grazing angle XRD (GAXRD), DC resistivity, atomic force microscopy (AFM) and magnetic force microscopy (MFM), respectively. GAXRD suggests that no significant change is observed in this system due to SHI irradiation. The average crystallite size increases with fluence, whereas the AFM image shows the rms roughness decreases due to irradiation with respect to the un-irradiated thin film. The MFM image shows that the magnetic interaction in irradiated film decreases due to the irradiation effect. Although the un-irradiated sample shows metal to semiconducting transition, but after irradiation with fluence of 5?×?1012 ions per cm2, the sharpness of the metal to semiconducting phase transition is observed to increase dramatically at ~300?K. This characteristic of the thin film makes it a promising candidate for an electrical switching device after irradiation. 相似文献
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采用微区Raman散射分析方法研究化学气相沉积法制备的金刚石膜的横截面.金刚石膜从衬底面到生长面不同位置具有不同特征的Raman谱,依此对膜中的金刚石、石墨和非晶碳成分进行分析.衬底面附近区域对应金刚石膜生长过程的成核阶段,非晶碳成分含量较高,相应于1200—1600cm-1波段较大的散射强度和存在较强的荧光背底.膜厚增大,非晶碳成分中sp3结构成分首先减少,而sp2结构成分和石墨成分的减少相对缓慢.而生长面附近区域只有比较单纯的晶体金刚石
关键词: 相似文献
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T. Tsuchiya M. Takeda I. Yamaguchi T. Manabe T. Kumagai S. Mizuta 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1541-1544
A SnO2 film has been prepared by an excimer laser metal organic deposition (ELMOD) process using an XeCl laser. The effects of the laser fluence, shot number, and the pretreatment temperature of the Sn acetylacetonate (Sn-acac) on the crystallization of the SnO2 film were investigated by X-ray diffraction and infrared spectroscopy. When the MO spin-coated film preheated at room temperature on a Si substrate was irradiated by the laser at a fluence of 100 mJ/cm2 and at a repetition rate of 10 Hz for 5 min, a crystallized SnO2 film was successfully obtained without heat treatment. At a fluence of 260 mJ/cm2, the highest crystalline film was formed. On the other hand, when the amorphous SnO2 film was irradiated by the laser at 260 mJ/cm2, the crystallinity of the SnO2 film was improved. SnO2 films were also prepared by conventional thermal MOD in a temperature range from 300 to 900 °C. The crystallinity of the SnO2 films prepared by the ELMOD process at room temperature was higher than that of the films prepared by heating at 900 °C for 60 min. PACS 81.15.Fg; 81.15.-z; 81.16.Mk; 82.50.Hp; 73.61.Le 相似文献
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P. GhodsO.B. Isgor J.R. BrownF. Bensebaa D. Kingston 《Applied Surface Science》2011,257(10):4669-4677
X-ray photoelectron spectroscopy (XPS) was used to study the properties of passive oxide film that form on carbon steel in saturated calcium hydroxide solution and the effect of chloride on the film properties. The thickness of the oxide films was determined to be approximately 4 nm and was not affected by the exposure time. Near the film/substrate interface the concentration of the Fe2+ oxides was higher than the concentration of the Fe3+ oxides; the layers near the free surface of the film mostly contained Fe3+ oxides. Chloride exposure decreased the thickness of the oxide films and changed their stoichiometry such that near the film/substrate interface Fe3+/Fe2+ ratio increased. 相似文献
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Yinfeng Liu Yuguang Li Liping Wang Beilei Gu Wenbin Sang Ying Gu 《Journal of Macromolecular Science: Physics》2013,52(2):230-241
Research on the preparation kinetics of nanosized materials is considered. The layered diffusion model (LDM) for S2? diffusing in a polymer–metal complex film, used for preparation of nanosized semiconductor metal sulfide by a coordination transformation method, is briefly introduced. An indirect measurement was employed to determine the concentration of residual S2? in the solution during the diffusion in a PVA–Cd2+ complex film. The relationship between the diffusion amount and the diffusion time shows that the diffusion curves are independent of the amount of Cd2+ in the film when the total amount of S2? is less than that of Cd2+. The experimental phenomena coincide basically with the theoretical curves deduced from LDM; thus they provide a proof for the LDM and the diffusion equations. The diffusion constant of S2? diffusing in PVA–Cd2+ complex film is about 1.7×10?3 cm2/s. 相似文献