Room temperature ferromagnetism of Co doped TiO2 using ion implantation and defect engineering

Ferromagnetic (FM) semiconductors obtained by doping ferromagnetic elements into a nonmagnetic semiconductor matrix are essential for the second generation of spintronics devices. In this study, we investigate Co doping behavior and subsequent magnetic properties in Co implanted and thermally annealed TiO₂. In TiO₂ single crystals, a decrease in the oxygen partial pressure during thermal annealing is found to enhance the Co substitutional fraction by increasing the concentration of oxygen vacancies. Magnetic properties determined from superconducting quantum interference device magnetometer (SQUID) measurements show that TiO₂ crystals with a large fraction of substitutional Co are ferromagnetic at room temperature. In addition to single crystals, the feasibility of Co doping via ion implantation is studied in sol–gel synthesized TiO₂ thin films. Results from grazing incidence X-ray diffraction (GIXRD) show that the implantation can produce Co doped TiO₂ thin films and that the Co incorporation into Ti lattice site accompanies the transition from rutile to anatase phase. These results show that ion beam synthesis is a useful tool for producing ferromagnetic TiO₂ with a high Curie temperature (T_C).     

Influence of nitrogen ion implantation energies on surface chemical bonding structure and mechanical properties of nitrogen-implanted silicon carbide ceramics

Nitrogen ions were implanted into silicon carbide ceramics (N⁺-implanted SiC) at different ions energies. The surface chemical bonding structure of N⁺-implanted SiC ceramics were investigated by using X-ray photoelectron spectroscopy (XPS). The hardness of N⁺-implanted SiC ceramics was measured using nano-indenter, and the friction and wear properties of the N⁺-implanted SiC/SiC tribopairs were studied using ball-on-disk type tribo-meter in water lubrication. The wear tracks were observed using non-contact surface profilometer and scanning electron microscope (SEM). The results showed that the surface roughness of N⁺-implanted SiC ceramic was higher than that of SiC ceramic, and some chemical bonds such as Si–N, C–C, CN and C–N bonds were formed in N⁺-implanted layer besides Si–C bonds. In comparison of SiC ceramic’s hardness, the hardness of N⁺-implanted SiC ceramics at 30 and 50 keV was higher while that at 65 keV was lower. Under water lubrication, the friction coefficient and the specific wear rates for the N⁺-implanted SiC/SiC tribopairs were all lower than those of the SiC/SiC tribopairs, and displayed the lowest values at 50 keV. According to XPS analysis, it was concluded that the high wear resistance and low friction coefficient for the N⁺-implanted SiC/SiC tribopairs were attributed to the formation of carbon rich composite on the surface of N⁺-implanted SiC ceramics.     

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。     

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。     

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。     

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.     

低能离子束辐照对纤维素微观结构变化的影响

采用红外光谱(IR),X射线衍射分析和扫描电镜(SEM)对低能离子(N+)注入纤维素粉微观结构的变化进行了研究。结果表明,低能离子辐照使纤维素分子内和分子间氢键均发生了断裂;随着辐照剂量的增加,纤维素相对结晶度逐渐减小,当注量增加到1500×1014cm-2时,相对结晶度较对照减少6.84%;纤维素颗粒直径逐渐变小,纤维变得越来越不完整,纤维表面出现较明显分层脱落现象,大多呈现的是细小碎片。     

Effects of Ag and Au ion implantation of lithium niobate

The optical effects of implantation of lithium niobate crystals with 100 keV Ag⁺ and 8 MeV Au³⁺ ions with fluences of 1 × 10¹⁷ ions/cm² have been investigated. Metal nanoparticle formation has been studied as a function of annealing temperature, and the resulting optical extinction curves have been simulated by the Mie theory in the small particle limit. Transmission electron microscopy (TEM) has provided direct evidence for the MNP sizes allowing comparison with the calculated results. A TEM study of an X-cut sample implanted with Ag⁺ ions show that the implanted region is partially amorphised. The differences in the temperature of Au colloid development in X- and Y-cut faces of the lithium niobate crystal are attributed to restoration of crystallinity as a result of annealing.     

Irradiation effects with 100 MeV Xe ions on optical properties of Al-doped ZnO films

Al-doped ZnO (AZO) films are known as n-type transparent semiconductors. We have investigated the effects of 100 MeV Xe ion irradiation on the optical and structural properties of AZO films, which were prepared on SiO₂ glass at 400 °C by using a RF-magnetron sputtering deposition method. We discuss relationships between these property modifications and the recent observations of the conductivity increase by ion irradiation. It is suggested that the band-gap modification has more close relation with the conductivity increase than the structural modification.     

SR-XRD和EXAFS研究Mn掺杂ZnO薄膜的微观结构

用射频磁控溅射技术在蓝宝石衬底上制备了一组不同衬底温度的Mn掺杂ZnO薄膜。质子激发X射线荧光(PIXE)测量表明,薄膜中仅有含量为5 at.%的Mn,未见其它磁性杂质元素(如Fe、Co、Ni等)。同步辐射X射线衍射(SR-XRD)表明,这些Mn掺杂ZnO薄膜具有纤锌矿ZnO结构。SR-XRD和扩展X射线吸收精细结构谱(EXAFS)分析显示,薄膜中未发现Mn团簇或MnO、MnO2、Mn2O3、Mn3O4等二次相,Mn原子是通过替代Zn原子而进入了ZnO晶格。     

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。     

离子注入甜菜杂交种当代生物效应

以甜菜杂交种为处理材料 ,用N+作为诱变源 ,以 35keV的能量 ,分别以 4 0次、6 0次脉冲 ,注入剂量分别为 4× 10 16 N+/cm2 和 6× 10 16 N+/cm2 进行激发诱变。结果显示 ,甜菜杂交种的产量、含糖率均有明显的提高。     

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。     

Structural characterizations and the third-order nonlinear optical properties of poly(2,5-didecyloxy)phenylene films modified by N ions implantation

Poly(2,5-didecyloxy)phenylene (PDDOP) films implanted by 30 keV nitrogen ions (N⁺) with the dose rang of 10¹⁵-10¹⁷ ions/cm² were characterized by FTIR-ATR spectra, UV-VIS spectra and X-ray photoelectron spectroscopy, which showed that the C-H bonds of the PDDOP films were largely broken and new bonds like CC, CN and CN were formed as the increasing ion fluence. The third-order nonlinear optical susceptibilities (χ⁽³⁾) were measured by degenerate four-wave mixing (DFWM) technique at 532 nm. The results demonstrated that the (χ⁽³⁾) value of PDDOP films was maximized to 4.19 × 10⁻¹¹ esu at an ion dose of 1.15 × 10¹⁷ ions/cm², which was 4.4 times larger than that of the pristine film. The enhanced third-order nonlinear properties may attribute to the enlarged expansion coefficient and the enhanced absorption coefficient of the bombarded films at proper N⁺ ions dose.     

氮离子注入铝的结构研究

采用掠射X射线衍射和AES方法分析了氮离子注入铝的结构和成分,采用TRIM?8程序对注入过程中氮浓度随深度的分布进行了模拟。结果表明:当温度低于300℃,能量为60 keV,用71017 /cm2和1?018 /cm2注量的氮离子注入铝时,在铝的表面生成了六方结构的AlN而不是立方结构的AlN;同时碰撞扩散作用在氮离子注入过程中居主导地位,热扩散作用和辐照增强扩散作用均不明显。     

向日葵种胚的V离子注入研究

利用扫描电子显微镜和能量色散谱仪研究Ｖ离子注入向日葵种胚后注入元素的深度分布,用透射电子显微镜（ＴＥＭ）研究离子注入前后子叶及胚轴部位细胞的显微结构变化。结果发现Ｖ离子在种皮层的注入深度达到１８μｍ,而在胚部位（如子叶、胚轴和胚根等）则没有测到Ｖ元素,注入前后子叶前后和胚轴细胞的显微结构在ＴＥＭ上没有明显的变化。     

Ti离子注入SiO_2合成TiO_2纳米颗粒及其光学性质

将105 keV的Ti离子注入到SiO_2玻璃至1×10~(17)、2×10~(17) cm~(-2),并在氧气气氛下进行热处理,借助紫外可见分光光度计、掠入射X射线衍射光谱仪、透射电子显微镜、原子力显微镜等多种测试仪器,详细研究了Ti O2纳米颗粒的形成、结构、分布及其光吸收和催化性能。研究结果表明,高注量Ti离子注入结合氧气气氛热处理可以在SiO_2基底中形成TiO_2纳米颗粒,并以金红石相为主。合成的TiO_2纳米颗粒的形貌明显依赖于离子的注量,随离子注量增加,形状不规则且分散排列的TiO_2纳米颗粒会转变成尺寸较为均匀、分布致密的纳米颗粒,进而形成了TiO_2类颗粒膜结构。另外,光催化降解实验结果表明,合成的纳米颗粒对罗丹明B溶液具有一定的降解作用。     

离子注入对超高分子聚乙烯磨损性能的影响

用８０ｋｅＶ不同剂量的Ｃ３Ｈ＾＋８,Ｎ＾＋２对超高分子聚乙烯样品进行离子注入,通过反冲探测分析表明注入层Ｈ含量的变化,对样品表面在离子注入前后的磨损性能进行了测试。实验结果显示,离子注入以后样品表面氢含量减少,磨损性能增强。     

Effect of Fe ion implantation on tribological properties and Raman spectra characteristics of diamond-like carbon film

1 Introduction It is well known that DLC (diamond-like carbon)prepared by physical vapor deposition, plasma en-hanced chemical vapor deposition (PECVD) and otherplasma processing is an amorphous carbon materialcontaining sp2 and sp3 bonded carbon atoms. DLCfilm possesses some interesting properties, such ashigh hardness and Young's modulus, chemical inert-ness and low friction coefficient. The property andstructure of DLC film can be modified by addingsome metals. Ion implantation…