Ge nano-layer fabricated by high-fluence low-energy ion implantation

A Ge nano-layer embedded in the surface layer of an amorphous SiO₂ film was fabricated by high-fluence low-energy ion implantation. The component, phase, nano-structure and luminescence properties of the nano-layer were studied by means of Rutherford backscattering, glancing incident X-ray diffraction, laser Raman scattering, transmission electron microscopy and photoluminescence. The relation between nano-particle characteristics and ion fluence was also studied. The results indicate that nano-crystalline Ge and nano-amorphous Ge particles coexist in the nano-layer and the ratio of nano-crystalline Ge to nano-particle Ge increases with increasing ion fluence. The intensity of photoluminescence from the nano-layer increases with increasing ion fluence also. Prepared with certain ion fluences, high-density nano-layers composed of uniform-sized nano-particles can be observed.     

Recharging processes, radiation induced strain and changes of OH bands under H ion implantation in Ti doped lithium niobate

A systematic analysis of variations in structural and optical characteristics of Z-cut plates of titanium doped congruent lithium niobate single crystals implanted with 120 keV proton beam at various fluences of 10¹⁵, 10¹⁶ and 10¹⁷ protons/cm² is presented. Through, high resolution X-ray diffraction, atomic force microscopy, Fourier transform infrared and UV-visible-NIR analysis of congruent lithium niobate, the correlation of properties before and after implantation are discussed. HRXRD (0 0 6) reflection by Triple Crystal Mode shows that both tensile and compressive strain peak are produced by the high fluence implantation. A distinct tensile peak was observed from implanted region for a fluence of 10¹⁶ protons/cm². AFM micrographs indicate mountain ridges, bumps and protrusions on target surface on implantation. UV-visible-NIR spectra reveal an increase in charge transfer between Ti³⁺/Ti⁴⁺ and ligand oxygen for implantation with 10¹⁵ protons/cm², while spectra for higher fluence implanted samples show complex absorption band in the region from 380-1100 nm. Variations of OH⁻ stretching vibration mode were observed for cLN Pure, cLNT2% virgin, and implanted samples with FTIR spectra. The concentration of OH⁻ ion before and after implantation was calculated from integral absorption intensity. The effect of 120 keV proton implantation induced structural, surface and optical studies were correlated.     

Quantitative characterization of xenon bubbles in silicon: Correlation of bubble size with the damage generated during implantation

Making use of Fresnel fringe contrast under different focusing conditions in transmission electron microscopy (TEM), we present a detailed evaluation of the depth dependent size distribution of gas bubbles contained in a stationary profile of 40 keV Xe implanted in Si. Voids generated during sample preparation by ion milling were also characterized carefully. The largest bubbles, with mean and maximum sizes of 5 and 7 nm, respectively, were observed at depths <22 nm. However, the first 2 nm of the sample did not contain any bubbles. Towards the end of range the bubble size decreased rapidly. No bubbles were found beyond 45 nm (the minimum size of detectable bubbles was estimated to be about 1.8 nm). Some observations suggest that the bubbles were over-pressurized. The derived data could be converted to a depth dependence of the Xe concentration contained in bubbles, n_Xe,b. Comparison with the previously reported depth distribution of Xe measured by Rutherford backscattering spectrometry (RBS), n_Xe,b turned out to be depth dependent, with a maximum of ∼28% in the region of maximum bubble size. n_Xe,b is shown to correlate closely with the damage density generated during Xe implantation. The findings lead to a model of bubble formation which involves the idea that the redistribution and transport processes initiated by ion impact take place mostly during the lifetime of the collision cascade.     

Active waveguides produced in lithium fluoride by He implantation

Planar active waveguides were produced in lithium fluoride crystals by implantation with 1.5 MeV He⁺ ions at several doses. The colored samples have been characterized by optical absorption, photoluminescence and m-line spectroscopy. By comparing the measured guided-mode effective indices with the ones calculated by means of the Chandler–Lama approach, the depth profile of refractive index was derived, showing that there are two competitive physical mechanisms, associated with different processes of energy deposition along the ion track, responsible for positive and negative modifications of the refractive index in the irradiated volume.     

Simulation of damage induced by ion implantation in Lithium Niobate

A simulation tool has been developed to engineer the damage formation in Lithium Niobate by ion irradiation with any atomic number and energy. Both nuclear and electronic processes were considered and, in particular, the dependence on the ion velocity of the electronic excitation damage efficiency has been taken into account. By using this tool it is possible both to draw damage nomograms, useful to qualitatively foresee the result of a given process, and to perform reliable simulations of the defect depth profiles, as demonstrated by the good agreement with the experimental data available in the literature.     

Defect engineering and micromachining of Lithium Niobate by ion implantation

A complete set of semi-empirical equations has been determined to engineer the damage formation in Lithium Niobate (LN) by irradiation with any ion atomic number and energy in the range 0.1–1.0 MeV/amu. Both nuclear and electronic process were taken into account and in particular the complex regime of sub-threshold electronic damage was quantitatively approached. The chemical etching of the processed material in 50 wt% HF at room temperature has been studied and the dependence of the etching rate on the damage concentration has been quantified. Finally, some test processes for surface micromachining of LN were first planned by using the above equations and then experimentally demonstrated.     

Refractive index tailoring in congruent Lithium Niobate by ion implantation

Refractive index profiles of ion-implanted Lithium Niobate waveguides are investigated. Z⁺ and z⁻ congruent Lithium Niobate samples have been implanted with C³⁺ ions at a fluence of 4 × 10¹⁴ ions/cm². Dark m-lines measurements have been performed on ordinary (n_o) and extraordinary (n_e) indexes for three different wavelengths (532 nm, 632.8 nm, 818 nm) before and after the annealing process. A reconstruction of refractive index profiles by Reflectivity Calculation Method (RCM) is presented and commented. The literature data for nuclear damage regime have been collected and critically examined. n_o and n_e curves as function of the density of energy released in nuclear collisions, E_d, describing the effects of ion implantation on LN refractive indexes has been obtained on the basis of literature data. n_o depth profile, predicted according to n_o(E_d) curve, is in good agreement with the RCM reconstructed one. In the case of n_e, a satisfactory agreement has been reached only slightly modifying the n_e(E_d) curve and considering an alternative RCM profile structure.     

聚苯胺的离子注入掺杂研究

研究了聚苯胺的离子注入掺杂对导电性的影响。用红外和紫外谱法探讨了聚苯胺的氧化态，本征态和还原态经离子注入后，其结构可能发生的变化。结果表明，聚苯胺的三种态的离子注入均为还原过程。讨论了离子注入掺杂的导电机制。     

Structure and thermal stability of Au–Fe alloy nanoclusters formed by sequential ion implantation in silica

Sequential ion implantation of Au and Fe ions has been performed in silica. Despite the fact that the two species are not miscible in the bulk, structural characterizations show that the nanoparticles produced are a Au–Fe alloy. The crystalline structure of the nanoparticles is fcc with a lattice parameter of 0.395 nm. The nanocomposite is ferromagnetic at 3 K, with a magnetic moment per Fe atom equal to 1.4μ_B and it shows a hysteresis loop with a coercive field of 24 mTorr. Due to alloying, the optical absorption spectrum does not exhibit the typical surface plasmon resonance of gold nanoparticles. The sample exhibits a change of its optical and structural properties when is annealed at 600 °C.     

中国科学院物理研究所的离子束分析及离子注入改性研究

介绍了中国科学院物理研究所离子束研究室的主要设备、分析方法、离子注入材料改性研究以及近年来在半导体材料、高Ｔｃ超导材料、环保等领域中的研究工作。     

离子束混合及离子注入陶瓷材料表面改性研究概述

对离子注入陶瓷材料引起的辐照损伤和材料力学性能、摩擦学性能的改善及陶瓷基体上金属薄膜的离子束混合增强粘着研究的进展进行了综述。     

离子注入生物分子的电荷交换效应

以酪氨酸分子晶体和腺嘌呤核苷分子晶体为对象，用毛细管电泳法研究荷能离子注入对其表面电荷的影响。     

离子注入技术在植物育种中的应用与研究进展

离子束作为一种新的诱变源,具有突变谱广、突变率高、生理损伤小的特点,并且具有一定的重复性和方向性。文章阐述了离子注入的特点、诱变机理和诱变效应,综述了诱变育种取得的进展,展望了离子注入技术的应用前景。     

Structure and morphology of ion irradiated Au nanocrystals in SiO2

We have investigated the effect of ion irradiation on the structure and morphology of Au nanocrystals (NCs) fabricated by ion beam synthesis in a thin SiO₂ layer on a Si substrate. Extended X-ray absorption fine structure (EXAFS) spectroscopy measurements show a significant drop in the average Au–Au coordination, as well as a loss of medium and long range order with increasing irradiation dose. Small angle X-ray scattering (SAXS) measurements reveal a concomitant reduction in average NC size. These observations are a consequence of structural disorder and collisional mixing induced by the irradiation. The observed reduction in average Au–Au coordination by EXAFS differs significantly from that estimated from the average NC sizes evaluated using SAXS. This behavior can be explained by the dissolution of Au NCs into the SiO₂ matrix. A significant bond-length contraction indicates that part of this material forms small Au clusters (dimers, trimers, etc.) during irradiation that cannot be detected by SAXS. Combining the results from SAXS and EXAFS measurements, we estimate the volume fraction of such clusters.     

Nanopatterning of silica with mask-assisted ion implantation

In the present paper we combined ion implantation and nanosphere lithography to regularly dope, by a mask-assisted process, a SiO₂ substrate with rare earth ions (Er) by ion implantation and to fabricate by sputtering a plasmonic 2D periodic array of Au nanostructures on the silica surface spatially coupled to the implanted Er³⁺ ions. The aim of this work is to study how Er³⁺ emission at 1.5 μm can be affected by the interaction with a plasmonic nanostructure. In particular we have found a variation of the radiative lifetime of the Er³⁺ emission and a change from single exponential to bi-exponential of the luminescence intensity decay.     

Effects of He ion implantation on surface properties of UV-cured Bis-GMA/TEGDMA bio-compatible resins

This work reports on the surface characterisation of 2,2-bis[4-(2-hydroxy-3-methacryloxyl-oxypropoxy)phenyl]propane/triethylene glycol dimethacrylate bio-compatible resins after high energy He⁺ ion implantation treatments. The samples have been characterised by diffuse reflectance FT-IR, X-ray photo-electron spectroscopy, ultramicro-hardness and nano-scratch wear tests. In addition, osteblast cell assays MG-63 have been used to test the bio-compatibility of the resin surfaces after the ion implantation treatments.It has been observed that the maximum surface hardening of the resin surfaces is achieved at He-ion implantation energies of around 50 keV and fluences of 1 × 10¹⁶ cm⁻². At 50 keV of He-ion bombardment, the wear rate of the resin surface decreases by a factor 2 with respect to the pristine resin. Finally, in vitro tests indicate that the He-ion implantation does not affect to the cell-proliferation behaviour of the UV-cured resins.The enhancement of the surface mechanical properties of these materials can have beneficial consequences, for instance in preventing wear and surface fatigue of bone-fixation prostheses, whose surfaces are continuously held to sliding and shearing contacts of sub-millimetre scale lengths.     

利用离子注入技术研制新型抗辐照太阳电池

利用离子注入技术在电池表面层形成密集的垂直ＰＮ结，缩短光生载流子到达ＰＮ结的距离，提高ＰＮ结的收集效率，从而研制成一种新型的抗辐照太阳电池。     

离子注入α－Al_2O_3陶瓷材料的表面改性研究

研究了α－Ａｌ２Ｏ３单晶注入Ｎ＋后的力学性能变化。结果表明，注入剂量为１×１０１７Ｎ＋／ｃｍ２时，Ａｌ２Ｏ３的显微硬度提高了９２％；注入剂量为３×１０１７Ｎ＋／ｃｍ２时，在Ａｌ２Ｏ３表面形成非晶层，导致表面软化，显微硬度只是基体的５０％左右．离子注入在样品表面产生了高达￣１１５０ＭＰａ的压应力，材料的断裂韧性的改善与此有关，实验亦发现Ｎ＋离子注入后Ａｌ２Ｏ３的断裂韧性提高了９５％左右．ＳＥＭ分析同样证明Ｎ＋注入ａ－Ａｌ２Ｏ３后，其表面力学性能确实有所改善。     

离子注入SOI薄膜材料的制备及性能

ＳＯＩ－ＣＭＯＳ电路具有高速度、低功能、抗辐照等优点。用氧、氮离子注入硅中,得到性能良好的ＳＩＭＯＸ和ＳＩＭＮＩ薄膜材料。用扩展电阻、霍耳效应和深能级瞬态谱等多种方法研究了ＳＯＩ材料表面界面的电学性能。并对各种方法进行了讨论。结果显示,用分步注入和分步退火制备的ＳＯＩ材料大大地改善了材料的电学性能。     

离子注入在番茄育种中的诱变功效

对番茄N+ 注入诱变效应进行了研究。结果表明,N+ 离子注入对番茄单果重、座果数等性状变幅大且变异率高;而对发芽率和果实的品质性状影响较小。以4×1016 / cm2 和6×1016 / cm2剂量处理,产量提高明显。不同品系、不同性状的最佳诱变剂量略有不同。