Si related defects in the VUV in silicon multi-energy implanted Type III silica

Some effects on the vacuum ultraviolet optical bands (6-8 eV) produced by implanted Si, using multi-energies ranging from 320 to 35 keV energies to produce a layer of constant concentration in (Type III) silica, approximately 600 nm thick, have been measured. Based on two methods of analyzing the spectra as a function of implanted layer concentration; first, by subtracting the spectrum of an un-implanted sample from each spectrum of the implanted samples and second, subtracting the spectrum of one concentration from the spectrum of the next largest concentration, we have identified band maxima. In the case of the first subtraction the maxima are at ∼7.54, 7.7, and 7.92 eV. In the case of the second subtraction the maxima are at ∼7.5, 7.85, and 7.95 eV. These difference spectra show that the various states have differing rates of increase with increase in Si concentration. The absorption between 6 and 7 eV increases with increasing Si concentration indicating that there is/are a band or bands in this region of the spectra. Because all of the bands that are resolved increase with increasing Si concentration we attribute these bands to Si related electronic states. An estimate of the oscillator strengths of these bands is made by comparison of their peak absorption with that of the E′ optical band at 5.83 eV, f = 0.14 ± 0.05, in the same samples. This comparison shows that all of the resolved bands between 6 and 8 eV have oscillator strengths equal to or larger than the E′ state, consistent with our assignment of the bands to Si related states. By comparing to the spectra from the Si implanted samples, the bands produced by radiation damage in an Ar implanted sample are between 7.3 and 8 eV bands are attributed to Si related states.     

锆离子轰击Zr-4的腐蚀行为及其慢正电子谱研究

为了研究锆离子轰击对Zr-4合金锆耐蚀性的影响,用金属蒸汽真空弧(MEVVA)源对纯锆样品进行了1?015 至2?017 cm-2 的锆离子轰击,加速电压为50 kV。用X-射线光电子谱(XPS)对轰击表面各元素进行价态分析;用俄歇电子能谱(AES)分析氧化膜厚度。对轰击样品进行3次极化测量,以评价轰击样品在1N 硫酸溶液中的耐蚀性。利用慢正电子谱研究了轰击样品表面的缺陷情况。研究结果表明:除1×1015cm-2剂量外,轰击样品的耐蚀性都好于空白Zr-4,且5×1016 cm-2离子轰击样品的耐蚀性最好,轰击样品的自腐蚀电位大体上随着剂量的增加而下降。轰击Zr-4样品的腐蚀行为与其慢正电子谱之间存在着一定的对应关系。     

Investigation of SPPO Membranes by Positron Annihilation Lifetime Spectroscopy

Positron annihilation lifetime spectroscopy （PALS） is a powerful technique to study the free volume in polymers. The lifetime of ortho-positronium （o-Ps）, a bound state of an electron and a positron, can be used to assess the pore size while the intensity can be used to characterize the number of pores. On the basis of the values of the long-lived o-Ps components in the lifetime spectra, the radii and fractional free volumes in the sulfonated poly （2,6-dimethyl-1,4- phenyleneoxide） （SPPO） membranes with different amounts of LiCl were calculated. It was found that, with the increasing amount of LiCl, the free volume radius and the fractional free volume firstly increased and then decreased. After immersing the membranes in distilled water, the free volume radius and the fractional free volume changed with different water concentrations in the membrane.     

X射线衍射法研究刚玉注入层的结构

用Ｘ射线衍射法和ＰＯＷＤ１２理论计算程序探讨了多晶刚玉Ｆｅ离子注入层的结构变化。     

Saturable absorption in gold implanted fused silica

Metal nanocluster composite glasses (MNCGs) have been the subject of both experimental and theoretical investigation because of their peculiar optical properties. In particular, the enhanced third order optical nonlinearity could be exploited in the all-optical switching device technology. In the present work, we present some results on MNCG films prepared by ion implantation. Fused silica were implanted with Au⁺ of fluences 3 × 10¹⁶ and 1 × 10¹⁷ ions/cm² using an energy of 1.5 MeV. Optical absorption spectra of these samples have revealed prominent linear absorption bands at characteristic surface plasmon resonance (SPR) wavelength at and around 490 nm. Rutherford backscattering spectrometry (RBS) measurements reveal a Gaussian spatial distribution of Au ions. Third order optical nonlinear properties were studied by the Z-scan technique using a nanosecond laser. Z-scan measurements on the metal nanoclusters glass composites have revealed saturable absorption signifying the nonlinear responses.     

高能铁离子辐照二氧化硅玻璃产生的缺陷研究

室温下用紫外-可见吸收光谱、荧光光谱和电子顺磁共振技术测量分析1.157 GeV56Fe离子辐照的二氧化硅玻璃,研究了高能重离子辐照产生缺陷的规律.紫外-可见吸收光谱测量结果显示,高能铁离子辐照产生了包括E'心、非桥连氧空穴心(NBOHC)和缺氧心ODC(Ⅱ)在内的多种缺陷结构.随着离子辐照量的增加,各类缺陷的数量逐渐增大并在高辐照量时趋于饱和.用单离子饱和损伤模型对实验结果进行拟合,获得了各类缺陷的产生截面在90-140 nm2.根据缺陷相对数量的变化关系探讨了E心和NBOHC的产生机制.荧光光谱显示,当以5 eV的紫外光激发辐照样品时,观测到三个荧光发射峰,分别位于4.28 eV(α带)、3.2 eV(β带)和2.67 eV(γ带),α带和γ带的存在证实辐照产生了ODC(Ⅱ)缺陷.实验发现β带是二氧化硅玻璃中的一种固有缺陷,高能离子辐照可使其部分脱色.电子顺磁共振测量进一步证实了E'心的产生规律.     

A Review of Studies of Polymeric Membranes by Positron Annihilation Lifetime Spectroscopy

A review is presented of studies of polymeric membranes by applying positron annihilation lifetime spectroscopy （PALS）. PALS has been used to study subnanometer-sized holes, to determine their size distribution and free-volume fractions, and to probe molecular-sized vacancies in glassy polymers. At present, PALS is believed to be a highly effective physical method for the examination of polymeric membranes.     

Heavy-ion-induced luminescence of amorphous SiO2 during nanoparticle formation

Silica glass was implanted with negative 60 keV Cu ions at an ion flux from 5 to 75 μA/cm² up to a fluence of 1 × 10¹⁷ ions/cm² at initial sample temperatures of 300, 573 and 773 K. Spectra of ion-induced photon emission (IIPE) were collected in situ in the range from 250 to 850 nm. Optical absorption spectra of implanted specimens were ex situ measured in the range from 190 to 2500 nm.

IIPE spectra showed a broad band centered around 560 nm (2.2 eV) that was assigned to Cu⁺ solutes. The band appeared at the onset of irradiation, increased in intensity up to a fluence of about 5 × 10¹⁵ ions/cm² and then gradually decreased indicating three stage of the ion beam synthesis of nanoclusters: accumulation of implants, nucleation and growth nanoclusters. The IIPE intensity normalized on the ion flux is independent on the ion flux below 20 μA/cm²at higher fluences. The intensity of the band increased with increasing samples temperature, when optical absorption spectra reveal the increase of Cu nanoparticles size.     

Raman scattering studies of oxygen implanted CdS thin films prepared by vacuum evaporation

CdS thin films prepared by vacuum evaporation method were implanted with oxygen ions at the energy of 80 keV to different doses. Raman scattering studies of the as-deposited and implanted films reveal the shift in the Raman peak position of A₁(LO) mode towards higher wave number on implantation. The area under the peak increases with dose initially, and then decreases at higher doses. The shift of the Raman peak to higher wave numbers has been attributed to the replacement of sulphur atoms by the lighter oxygen atoms.     

Study of annealing induced redistribution of implanted Au in Si: Fluence dependence

One hour 500 °C air annealing induced movement of implanted Au in Si have been studied for 32 keV Au implantation in Si, in the fluence range of . Samples were characterized using Rutherford backscattering spectrometry and cross-sectional transmission electron microscopy. The results indicate that, depending on the initial state of Au in the matrix, there is a clear difference in the diffusion behaviour of Au in Si. When Au is precipitated as gold-silicide nanoclusters inside the Si matrix, annealing is found to cause diffusion of Au into the bulk Si. Compared to this, for a random atomic distribution of Au in an amorphous Si matrix, annealing is found to result in out-diffusion of Au towards the surface.     

Size dependent hcp-to-fcc transition temperature in Co nanoclusters obtained by ion implantation in silica

In this work we present in situ investigations on the increase of the hcp-to-fcc transition temperature for Co with respect to the bulk value (420 °C) when nanoclusters are considered. Starting from Co:SiO₂ composites obtained by ion implantation with average Co cluster size of about 5 nm, a transition temperature between 800 °C and 900 °C is found upon thermal annealing in vacuum by in situ transmission electron microscopy. Preliminary results on electron irradiation to promote the transition at lower temperatures are presented.     

离子注入微生物产生"马鞍型"存活曲线的可能作用机制

研究了不同剂量的Ｎ＾＋注入耐辐射异常微球菌和大肠杆菌的存活与注入剂量的关系。结果表明,两者的存活曲线随着Ｎ＾＋注入剂量的增加均呈现为先降后升再降的“马鞍型”变化,完全不同于紫外线和γ射线辐射下的“肩形”和“直线形”本文根据已有的离子束生物工程学理论对这现象的可能作用机制进行了探讨。     

GCr15轴承钢N＋B离子注入层的XRD,AES和XPS研究

用X-射线衍射(XRD)、俄歇电子能谱(AES)和X-光电子能谱(XPS)的方法对N+B离子注入层的相组成、元素的分布和元素的结合状态进行了综合考察。结果表明:注入层是由基体中原有的α-Fe、Fe_3C相和注入过程中新生成的六方BN相和ε-Fe_2N-Fe_3N相组成的。另外,在注入层表面还有一层石墨型结构的碳膜存在。     

低能氮离子注入固态甘氨酸剩余产物的研究

采用２０ｋｅＶ Ｎ＾＋注入固态甘氨酸（Ｇｌｙ）薄膜。对注入样品的α粒子透射能谱以及样品溶于水后溶液的电导率和氨基含量的测量，揭示了低能离子注入的损伤作用具有饱和性。ＸＰＳ测量表明低能Ｎ＾＋注入Ｇｌｙ后形成了多种损伤产物，其中Ｃ、Ｎ元素的结合能变化较大，而Ｏ元素所处的化学环境变化很小。     

低束流钕离子注入外延硅薄层的结构研究

采用金属蒸气真空弧(MEWA)离子源以低束流方式将Nd离子注入到外延硅片中，经高温快速退火处理，制备了结晶良好的钕硅掺杂层。用扫描电子显微镜(SEM)、反射式高能电子衍射(RHEED)和X射线衍射(XRD)分析了在不同退火条件下样品注入层相结构的变化。研究结果表明，经高温热处理，注入层形成结晶良好的钕硅化合物，出现由Nd5Si4相向NdSi相转变的趋势。并对其转变过程进行了初步探讨。     

Pb离子辐照注碳a-SiO2薄膜的光致发光性能

用湿氧化法在单晶硅表面生长了非晶态SiO2薄膜,进行120 keV C离子注入和950 MeV Pb离子辐照,用荧光光谱分析样品发光特性的改变.结果发现,C离子注入和高能Pb离子辐照均能显著影响样品的发光特性,且荧光光谱的改变强烈依赖于注入和辐照剂量,预示不同注入和辐照剂量将导致不同的发光结构形成.对注入和辐照造成薄膜...     

Enhanced nucleation of Ag nanoparticles by vacancy-type defects in Ar-ions implanted spinel

Vacancy-type defects are introduced into magnesium aluminate spinel (MgAl₂O₄ (1 1 0)) by Ar-ions implantation, and then Ag-ions are implanted into the depth rich in vacancy-type defects. The ultraviolet-visible spectrometry (UV-VIS) and positron annihilation spectroscopy (PAS) are used to study the influence of vacancy-type defects on nucleation of Ag nanoparticles. After introduction of vacancy-type defects the pronounced increase of surface plasmon resonance (SPR) absorbance intensity indicates that defects enhance the nucleation of Ag nanoparticles. The PAS results reveal that vacancy-type defects provide pre-nucleating centers for Ag nanoparticles nucleation and growth.     

背散射分析钇离子注入H13钢的抗氧化特性

用背散射技术测量了不同注入剂量和大束流密度的Y~+注入H_(13)钢的浓度分布,并研究了注入样品的抗氧化特性。结果表明,Y的浓度分布和峰值浓度的变化与注入剂量和束流密度密切相关。Y峰值浓度大小对抗氧化特性有直接的影响。Y~+注入钢改变了钢的氧化模式。氧的扩散受到控制。高温(800℃)氧化10min即可形成抗氧化的氧化皮。Y~+的注入可使氧化速率下降8倍。     

Penetration depth and concentrationdistribution for implanted heavy ions with low energies in plant seeds bySEM and EDS

The penetration depth and concentration distribution of implanted ions have been studied for low energy heavy ions implanted in the dry seeds of plant,such as peanut,mung bean,sunflower,wheat and radish seeds,etc.by SEM EDS.The results show that the maximum penetration depth is about 12μm for V^ with an energy 200keV implanted in cotyledon of the peanut,18μm,15μm,20μm for V^2 with 90keV implanted in sunflower,wheat,radish seeds,respectively.The penetration depth of implanted Cu^2 with 80keV is about 90μm in the remainder funicle derivative of the mung bean seeds.The experimental result of the maximum penetration depth of implanted V^ in the peanut seeds was compared with the calculated value of the TRIM95.