荷能离子在C60薄膜中引起的辐照效应

用 Raman散射和 XPS技术分析了能量为几百 ke V到几百 Me V的多种离子在 C60 薄膜中引起的辐照效应.分析结果表明 ,在低能重离子辐照的 C60 薄膜中 ,其晶态向非晶态的转变过程是由核碰撞主导的.在快离子 (1 2 0 ke V的 H离子和171.2 Me V的 S离子 )辐照的情况下,电子能损起主导作用.发现在H离子辐照过程中,电子能损有明显的退火效应 ,致使 C60 由晶态向非晶态转变的过程中,经历了一个石墨化的中间过程;而在 S离子辐照的情况下 ,电子能损的破坏作用超过了退火效应 ,因此 ,在C₆₀ 由晶态向非晶态转变的过程中,无石墨化的中间过程.Irradiation effecs (mainly including transformation from crystalline into amorphous state) of C 60 films induced by 120 keV H, He, N, Ar, Fe and Mo ions, 240 keV and 360 keV Ar ions, and 171.2 MeV, 125.3 MeV and 75.8 MeV S ions were analysed by means of Raman scattering and XPS technique. The analysis results indicate that amorphization process in the cases of N, Ar, Fe and Mo ions irradiation is dominated by nuclear collision, but in the case of H ion irradiation, the process is...     

快重离子辐照C60薄膜的强电子激发效应研究

利用能量为2.0GeV的¹³⁶Xe和2.7GeV的²³⁸U离子对C₆₀薄膜进行了辐照,并用傅立叶变换红外光谱、X射线衍射谱和拉曼散射技术分析了辐照过的C₆₀样品,在傅立叶变换红外光谱上,首次观察到一个位于670cm^－1处的,表征未知结构的新峰,研究了其强度随电子能损和辐照剂量的变化规律.分析结果表明,电子能量转移主导了C₆₀薄膜的损伤过程;而损伤的部分恢复是由强电子激发的退火效应引起的;另外,离子的速度在损伤的建立过程中也起了一定的作用     

FePc与TiO2(110)及C60界面电子结构研究

基于C₆₀受体和有机分子给体的太阳能电池是目前非常重要的一个研究热点, 利用同步辐射真空紫外光电子能谱(SRUPS) 技术研究了酞菁铁(FePc)与TiO₂(110)及C₆₀的界面电子结构, 以及FePc与C₆₀分子混合薄膜的电子结构. SRUPS价带谱显示, FePc沉积在化学计量比与还原态两种不同的TiO₂(110)表面时, FePc分子的HOMO能级均随FePc厚度的变化发生了移动, 而在化学计量比的TiO₂(110)表面位移较大, 同时发生界面能带弯曲, 说明存在从有机层向衬底的电子转移. 在FePc/C₆₀和C₆₀/FePc界面形成过程中, FePc与C₆₀分子的最高占据分子轨道(HOMO)位移大小基本相同. 由界面能级排列发现, 在FePc与C₆₀的混合薄膜中, FePc分子的HOMO与C₆₀分子的最高占据分子轨道能级差较大, 这有利于提高器件开路电压, 改善器件性能.     

电子束在VO2薄膜中引起的价态、相结构和光学性能的改变

 利用能量为1.7MeV, 注量分别为1.25×10¹³/cm², 1.25×10¹⁴/cm², 1.25×10¹⁵/cm²的电子束辐照VO₂薄膜,采用XPS, XRD等测试手段对电子辐照前后的样品进行分析,并研究了电子辐照对样品相变过程中光透射特性的影响。结果表明电子辐照引起VO₂薄膜中V离子出现价态变化现象,并使薄膜的X射线衍射峰发生变化。电子辐照在样品中产生的这些变化显著改变了VO₂薄膜的热致相变光学特性。     

不同粒径α-Al2O3:C晶态粉体热释光和光释光特性

本文探讨了α -Al₂O₃:C晶态粉体的辐照剂量效应, 使用RisøTL/OSL-DA-15 型热释光和光释光仪研究其热释光和光释光特性, 结果发现, 相同粒径的α-Al₂O₃:C晶态粉体具有单一热释光峰, 且随着辐照剂量的增加热释光强度不断增加, 但热释光峰位置保持不变, 符合一级动力学模型; 而在相同的辐照剂量和测试条件下, 随着α -Al₂O₃:C晶态粉体粒径的减小, 其热释光强度先增强后减弱, 热释光峰却逐渐增加至趋于稳定, 表明粒度为40—60 μ的α -Al₂O₃:C晶态粉体具有最佳的热释光效应. 同时α -Al₂O₃:C晶态粉体的光释光特性的研究发现, 其光释光曲线具有典型的指数衰减特征, 粒径对其光释光强度和衰减速率的影响符合浅电子陷阱能级理论.     

K3C60取向相变的同步辐射光电子谱研究

在190K,220K和300K3个不同温度下测量了K₃C₆₀单晶薄膜沿[111]方向发射的同步辐射角分辨光电子谱.样品温度为190K时,能够观察到导带有规律的角散,并且带结构与已报道的温度为150K时的结果基本一样.而在220K附近,导带的许多子峰消失,色散不再存在.这两个温度的实验结果与K₃C₆₀在200K存在取向相变相符合,并且可在反铁磁Ising模型基础上得到理解.这种模型的定量分析结果还首次对K₃C₆₀在200K的相变机理作出了解释,即相变是由低温下的一维无序取向结构转变为200K以上的双取向结构畴与无序分子(约占40%)的混合.室温光电子谱与低温下的结果显著不同,对应于C₆₀分子取向在室温附近的动态无序.     

离子注入对C60薄膜结构的影响

利用高能离子注入技术系统地研究了不同剂量、不同种类离子注入对C₆₀薄膜结构的影响,并利用Raman光谱对其结构进行分析．结果表明：中等能量的离子注入会影响C₆₀薄膜的结构,使C₆₀分子薄膜产生聚合和非晶碳化现象,但上述现象的出现与注入离子的剂量大小有关,并存在一注量阈值,只有在此阈值之上,C₆₀薄膜结构才发生改变,研究表明这与注入离子同C₆₀分子之间互作用方式有关.     

n型透明导电薄膜CdIn2O4电学性质的研究和大面积制备的最佳条件

在Ar+O2₂气氛中，采用射频反应溅射Cd-In靶制备CdIn2₂O4₄ 薄膜.制得的薄膜经x射线衍射（XRD）检测为CdIn2₂O4₄和CdO相组成的多晶.从理论上分析了热 处理前后氧空位、掺杂点缺陷和富氧电子陷阱在影响膜的载流子浓度和电子散射中所起的重要作用.同时，对样品 进行Hall效应、Seebeck效应测试并得出不同载流子浓度下的迁移率、有效质量、弛豫时间以及它们之间的相互关系，特别强调     

TeOx薄膜结构及短波长静态记录特性的研究

以真空蒸镀法在K9玻璃基底上制备了TeO_x单层薄膜.使用X射线光电子能谱仪(XPS)、X射线衍射仪(XRD)、原子力显微镜(AFM)对薄膜的结构进行了分析.实验结果表明,薄膜是由晶态Te分散在非晶态TeO₂基体中形成的混合体系,TeO₂基体的存在增强了Te的抗氧化性能;薄膜具有精细粒状结构和粗糙的表面;退火后薄膜的反射率增加和Te向表面的偏析、重聚集及表面粗糙度的降低有关.采用波长为514.4nm的短波长静态记录仪对薄膜静态记录性能的测试结果表明:薄膜具有良好的记录灵敏性,在记录功率1.5mW、脉宽50ns时就可产生较高的反射率衬比(度).研究结果为选择合适掺和物使TeO_x薄膜实际用作高密度光存储介质有重要意义.     

Ar离子辐照非晶态合金引起的尺寸变化

利用兰州重离子加速器(HIRFL)提供的2.79MeV/u Ar离子,在50K以下的低温辐照了Fe₄₇Ni₂₉V₂Si₆B₁₆等4种非晶态合金样品,室温下使用光学显微镜对辐照前、后的同一样品拍照,对比测量了样品的宏观尺寸. 结果表明:在辐照剂量为1.5×10¹⁴离子/cm²时,非晶态合金形变不明显,测量到的样品宽度相对增长Δb/b₀均小于1.0%;当辐照剂量增加到1.6×10¹⁵离子/cm²时,所有非晶态合金样品都发生了显著的形变,其宽度相对增长分布在4.3%—12.0%之间,对此结果进行了定性的分析.     

Irradiation Effect in C60 Films Induced By Low Energy Ions

Irradiation effecs, mainly including transformation from crystalline into amorphous state, of C₆₀, films induced by 120keV H, Ar and Fe ions irradiation were analysed by means of Raman scattering technique. The results indicate that amorphization process in the cases of Ar and Fe ions irradiation is dominated by nuclear collision, but in the case of H ion irradiation, the process is dominated by electronic energy transfer. The annealing effect of electronic energy loss which induced the intermediate graphitization process before amorphization in lower irradiation dose ranging from 2×10¹⁴ ions/cm² to 5×10¹⁶ ions/cm² was found in the case of H ion irradiation for the first bine.     

快重离子辐照引起Ni/SiO2界面原子混合及相变研究

在室温下用308 MeV的Xe离子和853 MeV的Pb离子辐照Ni/SiO2样品, 用卢瑟福背散射和X射线衍射技术对样品进行了分析。 通过分析Ni/SiO2样品中元素成分分布和结构随离子辐照剂量和电子能损的变化, 探索了离子辐照在Ni/SiO2样品中引起的界面原子混合与结构相变现象。 实验结果显示, Xe和Pb离子辐照均能引起明显的Ni原子向SiO2基体的扩散并导致界面附近Ni, Si和O原子的混合。 实验观测到低剂量Xe离子辐照可产生NiSi2相, 而高剂量Xe离子辐照则导致了Ni3Si和NiO相的形成。 根据热峰模型, Ni原子的扩散和新相的形成可能由沿离子入射路径强电子激发引起的瞬间热峰过程驱动。Ni/SiO2 interface were irradiated at room temperature with 308 MeV Xe ions to 1×1012, 5×1012 Xe/cm2 and 853 MeV Pb ions to 5×1011 Pb/cm2, respectively. These samples were analyzed using Rutherford Backscattering Spectrometry (RBS) and X ray diffraction spectroscopy (XRD), from which the intermixing and phase change were investigated. The obtained results show that both Xe and Pb ions could induce diffusion of Ni atoms to SiO2 substrates and result in intermixing of Ni with SiO2. Furthermore, 1.0×1012 Xe/cm2 irradiation induced the formation of NiSi2 and 5.0×1012 Xe/cm2 irradiation created Ni3Si and NiO phases. The diffusion of Ni atoms and the formation of new phase may be driven by a transient thermal spike process induced by the intense electronic energy loss along the incident ion path.     

Fe/Nb多层膜中离子辐照效应研究(英文)

〗采用磁控溅射技术在Si衬底上沉积Si/\[Fe(10 nm)/Nb(4 nm)/Fe(4 nm)/Nb(4 nm)\]2/ \[Fe(4 nm)/Nb(4 nm)\]4多层膜。 用2 MeV的 Xe离子在室温下辐照多层膜。采用俄歇深度剖析、X射线衍射和振动样品磁强计分析辐照引起的多层膜元素分布、 结构及磁性变化。AES深度剖析谱显示当辐照注量达到1.0×1014 ions/cm2时, 多层膜界面两侧元素开始混合; 当辐照注量达到2.0×1016ions/cm2时, 多层膜层状结构消失, Fe层与Nb层几乎完全混合。XRD谱显示, 当辐照注量达到1.0×1014ions/cm2时, Nb的衍射峰和Fe的各衍射峰的峰位相对于标准卡片向小角方向偏移, 这说明辐照引起Nb基和Fe基FeNb固溶体相的形成;当辐照注量大于1.0×1015 ions/cm2时, 辐照引起非晶相的出现。 VSM测试显示,多层膜的磁性随着结构的变化而变化。 在此实验基础上, 对离子辐照引起界面混合现象的机理进行了探讨。The behavior of the metallic multilayers of Si/\[Fe(10 nm)/Nb(4 nm)/Fe(4 nm)/ Nb(4 nm)\]2/\[Fe(4 nm)/Nb(4 nm)\]4 under 2 MeV Xe ion irradiation has been investigated by depth profile analysis of Auger electron spectroscopy,X ray diffraction and vibrating sample magnetometer. The obtained experimental results show that the inter mixing between Fe and Nb layers occurs in the 1.0×1014 ions/cm2 irradiated multilayer sample which results in the formation of Nb based and Fe based FeNb solid solution. For the samples irradiated to fluence larger than 1.0×1014 ions/cm2, amorphisation is observed, and moreover, the layered structure of the multilayer samples is broken up completely for the samples under 1.0×1016 or 2.0×1016 ions/cm2 irradiation. Vibrating sample magnetometer measurement also reveals that the magnetization of the samples changes with the evolution of the structure of multilayers. Possible mechanism of the modification in Fe/Nb multilayers induced by Xe ion irradiation is briefly discussed.     

GeV能量的Fe离子在C60薄膜中的辐照效应研究

利用傅立叶转换红外光谱和Raman谱仪分析了0.98 GeV的Fe离子在电子能损Se为3.5 keV/nm时， 不同辐照剂量（5×1010 —8×1013 ions/cm2)下， 在C60薄膜中引起的辐照损伤效应。 分析表明， Fe离子辐照引起了C60分子的聚合与损伤。 在辐照剂量达到一中间值1×1012 ions/cm2， C60分子的损伤得到部分恢复， 归因于电子激发引起的退火效应。 通过对Raman数据的拟合分析， 演绎出Fe离子辐照在C60材料中形成的潜径迹截面或引起损伤的截面约为1.32×10-14 cm2。     

聚合物材料的快重离子辐照效应

简要介绍了快重离子辐照损伤的特点,通过与低电离辐射粒子辐照在聚合物材料中产生的效应的类比论述了快重离子辐照在聚合物材料中产生的效应及其研究现状 ,并结合快重离子辐照效应的应用展望了该领域未来的发展.The irradiation effects in polymers induced by swift heavy ions were reviewed in comparison with that induced by low ionization particles based on the characteristics of swift heavy ion irradiations. It is shown that bond breaking and cross linking, gas releasing, amorphization and carbonization of polymers depend strongly on the electronic energy loss. Besides special effects such as alkynes production, can be induced under swift heavy ion irradiation. The perspectives...     

Swift heavy ion irradiation induced modification of BiFeO3 thin films prepared by sol-gel method

We report the preparation of multiferroic BiFeO₃ thin films on ITO coated glass substrates through sol-gel spin coating method followed by thermal annealing and their modification by swift heavy ion (SHI) irradiation. X-ray diffraction and Raman spectroscopy studies revealed amorphous nature of the as deposited films. Rhombohedral crystalline phase of BiFeO₃ evolved on annealing the films at 550°C. Both XRD and Raman studies indicated that SHI irradiation by 200 MeV Au ions result in fragmentation of particles and progressive amorphization with increasing irradiation fluence. The average crystallite size estimated from the XRD line width decreased from 38 nm in pristine sample annealed at 550°C to 29 nm on irradiating these films by 200 MeV Au ions at 1 × 10¹¹ ions cm⁻². Complete amorphization of the rhombohedral BiFeO₃ phase occurs at a fluence of 1 × 10¹² ions.cm⁻². Irradiation by another ion (200 MeV Ag) had the similar effect. For both the ions, the electronic energy loss exceeds the threshold electronic energy loss for creation of amorphized latent tracks in BiFeO₃.     

Thermal processes in multilayer second-generation HTSC under swift heavy-ion irradiation

On the basis of the thermal spike model, the estimations with regard to tapes of the second-generation Ag/YBaCuO/MgO/Hastelloy HTSC under irradiation with Ar, Kr, and Xe ions of an energy of about 1.2 MeV/amu have been carried out. The results have been compared with the available experimental data. In addition, the possibility of processes such as melting, recrystallization, amorphization, and other phase transitions in multilayer structures under ion irradiation has been studied.     

56Fe13+离子引起GaP晶体的微结构损伤

利用X射线衍射（XRD）技术、傅里叶变换红外光谱（FTIR）和Raman光谱对经不同剂量的56Fe13+离子辐照的GaP晶体的微结构进行了表征。结果表明:随着辐照离子剂量的增加,GaP晶体中产生了局部的无序与缺陷。随着56Fe13+离子剂量的增加,Raman光谱展示出振动峰强度逐渐减弱而且一些逐渐消失,但其峰位几乎没有发生变化;XRD显示出GaP晶体的衍射峰的强度逐渐减小;FTIR主要表现为宽化及其强度增加。这表明重离子56Fe13+的辐照使得GaP晶体中的缺陷与无序性增加,导致晶体产生了局部的非晶化。The Misconstructural damage of GaP irradiated with 56Fe13+ to fluences ranging from 1×107 ions/cm2~1×1010 ions/cm2 were analyzed by X-ray diffraction (XRD) techniques, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The result shows that, with the increase of irradiation ion fluences, local disorder and defects were produced in GaP crystal. With the increase of ion fluence, Raman spectra reveal the intensity of scattering peaks gradually weakens and some scattering peaks gradually disappear, however no changes in the peak position were found. XRD measurement displays that the intensity of diffraction peaks gradually decreases with an increase in ions fluences. Result from FTIR spectra exhibits that the intensity of reflection peaks gradually increases and the FWHM of reflection peaks broadens. These phenomena indicate that, the irradiation of heavy-ion Fe produces defects and disorder in GaP crystal, leading to a local amorphization.