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.     

Implantation of anatase thin film with 100 keV Fe ions: Damage formation and magnetic behaviour

We have investigated the damage morphology and magnetic properties of titanium dioxide thin films following implantation with Fe ions. The titanium dioxide films, having a polycrystalline anatase structure, were implanted with 100 keV ⁵⁶Fe⁺ ions to a total fluence of 1.3 × 10¹⁶ ions/cm². The ion bombardment leads to an amorphized surface with no indication of the presence of secondary phases or Fe clusters. The ion-beam induced damage manifested itself by a marked change in surface morphology and film thickness. A room temperature ferromagnetic behaviour was observed by SQUID in the implanted sample. It is believed that the ion-beam induced damage and defects in the polycrystalline anatase film were partly responsible for the observed magnetic response.     

Ion beam characterization of Fe-implanted GaN

Fe ion implantation in GaN has been investigated by means of ion beam analysis techniques. Implantations at an energy of 150 keV and fluences ranging from 2 × 10¹⁵ to 1 × 10¹⁶ cm^?2 were done, both at room temperature and at 623 K. Secondary Ions Mass Spectrometry was used to determine the Fe implantation profiles, whereas Rutherford Backscattering in channeling conditions with a 2.2 MeV ⁴He⁺ beam allowed us to follow the damage evolution. Particle Induced X-ray Emission in channeling conditions with a 2 MeV H⁺ beam was employed to study the lattice location of Fe atoms after implantation. The results show that a high fraction of Fe-implanted atoms are located in high symmetry sites in low fluence implanted samples, where the damage level is lower, whereas the fraction of randomly located Fe atoms increases by increasing the fluence and the resulting damage. Moreover, dynamical annealing present in high temperature implantation has been shown to favor the incorporation of Fe atoms in high symmetry sites.     

Helium and deuterium implantation in tungsten at elevated temperatures

High temperature helium and deuterium implantation on tungsten has been studied using the University of Wisconsin inertial electrostatic confinement device. Helium or deuterium ions from a plasma source were driven into polished tungsten powder metallurgy samples. Deuterium implantation did not damage the surface of the specimens at elevated temperatures (∼1200 °C). Helium implantation resulted in a porous surface structure above 700 °C. A helium fluence scan, ion energy scan, and temperature scan were all completed. With 30 keV ions, the pore formation started just below 4 × 10¹⁶ He⁺/cm². The pore size increased and the pore density decreased with increasing fluence and temperature. The energy scan from 20 to 80 keV showed no consistent trend.     

Effect of swift heavy ion irradiation on structural, optical and electrical properties of Cd2SnO4 thin films

Transparent conducting cadmium stannate thin films were prepared by spray pyrolysis method on Corning substrate at a temperature of 525 °C. The prepared films are irradiated using 120 MeV swift Ag⁹⁺ ions for the fluence in the range 1 × 10¹² to 1 × 10¹³ ions cm⁻² and the structural, optical and electrical properties were studied. The intensity of the film decreases with increasing ion fluence and amorphization takes place at higher fluence (1 × 10¹³ ions cm⁻²). The transmittance of the films decreases with increasing ion fluence and also the band gap value decreases with increasing ion fluence. The resistivity of the film increased from 2.66 × 10⁻³ Ω cm (pristine) to 5.57 × 10⁻³ Ω cm for the film irradiated with 1 × 10¹³ ions cm⁻². The mobility of the film decreased from 31 to 12 cm²/V s for the film irradiated with the fluence of 1 × 10¹³ ions cm⁻².     

Effect of methane content and the oscillating electric field between electrodes on atmospheric Ar/methane plasma jet and DLC coating deposition

In this work, the effects of the methane gas flow and the internal oscillating electric field between electrodes on radio-frequency(RF) atmospheric pressure argon/methane plasma jet and process of diamond-like carbon(DLC) film deposition have been investigated. Properties of RF atmospheric Ar/methane plasma jet such as active species density, length, electron temperature,appearance and ionization process of argon/methane plasma jet are changed due to the changing of methane flow content and electric field vector and its gradient. With increasing methane flow,the formation of C2 hydrocarbon and CH band content is decreased because injected electrical energy to a mixture of Ar/methane gases is insufficient to stabilize the ionization process of methane gas and the electrical-chemical reaction rate is decreased. With shortening the gas gap between two electrodes, electric field strength and its gradient are increased leading to more energy injection to the electron. Electrical-chemical reactions are strengthened leading to increasing the CH band content. These phenomena introduce the Ar/methane plasma jet in different modes causing to deposit the DLC film with different structures and properties. With using quartz glass and alumina ceramic as dielectric barriers tubes, RF atmospheric pressure Ar/methane plasma jet has been used to deposit DLC coating in different modes. Increasing methane content and shortening the gas gap leads to decreasing sp3 bonded content and the quality of the deposited film.     

High yield antibiotic producing mutants of Streptomyces erythreus induced by low energy ion implantation

Conidia of Streptomyces erythreus, an industrial microbe, were implanted by nitrogen ions with energy of 40–60 keV and fluence from 1 × 10¹¹ to 5 × 10¹⁴ ions/cm². The logarithm value of survival fraction had good linear relationship with the logarithm value of fluence. Some mutants with a high yield of erythromycin were induced by ion implantation. The yield increment was correlated with the implantation fluence. Compared with the mutation results induced by ultraviolet rays, mutation effects of ion implantation were obvious having higher increasing erythromycin potency and wider mutation spectrum. The spores of Bacillus subtilis were implanted by arsenic ions with energy of 100 keV. The distribution of implanted ions was measured by Rutherford Backscattering Spectrometry (RBS) and calculated in theory. The mechanism of mutation induced by ion implantation was discussed.     

The damaging effects of nitrogen ion beam implantation on upland cotton (Gossypium hirsutum L.) pollen grains

With the aim to study the effects of an ion beam on plant cells, upland cotton (Gossypium hirsutum L.) cultivar “Sumian 22” pollen grains were irradiated in vacuum (7.8 × 10⁻³ Pa) by low-energy nitrogen ions with an energy of 20 keV at various fluences ranging from 0.26 × 10¹⁶ to 0.78 × 10¹⁶ N⁺/cm². The irradiation effects on pollen grains were tested, considering the ultrastructural changes in the exine and interior walls of pollen grains, their germination rate, the growth speed of the pollen tubes in the style, fertilization and boll development after the pistils were pollinated by the pollen grains which had been implanted with nitrogen ions. Nitrogen ions entered the pollen grains by etching and penetrating the exine and interior walls and destroying cell structures. A greater percentage of the pollen grains were destroyed as the fluence of N⁺ ions increased. Obviously, the nitrogen ion beam penetrated the exine and interior walls of the pollen grains and produced holes of different sizes. As the ion fluence increased, the amount and the density of pollen grain inclusions decreased and the size of the lacuna and starch granules increased. Pollen grain germination rates decreased with increasing ion fluence. The number of pollen tubes in the style declined with increased ion implantation into pollen grains, but the growth speed of the tubes did not change. All of the pollen tubes reached the end of the style at 13 h after pollination. This result was consistent with that of the control. Also, the weight and the diameter of the ovary decreased and shortened with increased ion beam implantation fluence. No evident change in the fecundation time of the ovule was observed. These results indicate that nitrogen ions can enter pollen grains and cause a series of biological changes in pollen grains of upland cotton.     

Etching and structure changes in PMMA coating under argon plasma immersion ion implantation

A thin (120 nm) polymethylmethacrylate coating was treated by plasma immersion ion implantation with Ar using pulsed bias at 20 kV. Ellipsometry and FTIR spectroscopy and gel-fraction formation were used to detect the structure transformations as a function of ion fluence. The kinetics of etching, variations in refractive index and extinction coefficient in 400-1000 nm of wavelength, concentration changes in carbonyl, ether, methyl and methylene groups all as a function of ion fluence were analyzed. A critical ion fluence of 10¹⁵ ions/cm² was observed to be a border between competing depolymerization and carbonization processes. Chemical reactions responsible for reorganization of the PMMA chemical structure under ion beam treatment are proposed.     

Reduction and compensation of lattice stress in high energy P+ and P+Sb implanted silicon

1IntroductionIontwlantationisaYerywtortantVLSItechnology.High-energyionimPlanta-tionhasattractedmuchinterestasitmayplayanimportantroleincreatingdeepp-njunctions,buried1ayers,deepburiedconnectionsbetweendevices,p-well,andn-well,whichareassociatedwithVLSIcircultfabri.ati..[1~3].InordertoapplyMeVenergyionforlantationtechnologytodevicefabrication,thestructure,natureanddepthdis-tributionofdefectsinimplantedandannealedsillconshouldbecarefullyinvestigated.Moreover,itisalsonecessarytopaycloseatte…     

Effect of the displacement damage from argon ion irradiation on the synergistic effect of helium–hydrogen in tungsten

The effect of argon ion pre-irradiation on helium and hydrogen ion irradiation was investigated in tungsten. At the same time, comparative experiments were carried out on the irradiation of helium and hydrogen ions in tungsten. Without the argon ion irradiation, the energy of 35 keV hydrogen ions mainly accelerated the coalescence of defects created by the 60 keV helium ions, the irradiation damage degree increased with hydrogen ion fluence increasing. With the argon ion irradiation, lots of voids were created by argon ion irradiation, which increased the helium and hydrogen retention and the synergistic effect of helium–hydrogen in tungsten. In the same hydrogen fluence, the surface damage degree with argon ion pre-irradiation was higher than that without argon ion pre-irradiation.     

离子注入在刀具上应用的研究

能量为几十千到几百千电子伏离子射入材料表面,使表面层的组成与结构发生改变,从而引起材料表面的物理与化学性质的变化,这种材料改性方法有极其重要的应用。如摩擦、润滑性、耐磨损性、表面硬化、抗高温氧化性、耐腐蚀性、催化及附着力改善等。虽然离子注入可改善材料这些性质,但由于经济与技术上的原因,最重要的研究集中在耐磨损性、抗高温氧化性及某些耐蚀性上,而耐磨性的研究以工具上的应用为最多。     

Photoluminescence from neodymium silicide thin films formed by MEVVA ion source

Neodymium silicides were synthesized by Nd ion implanted into Si substrates with the aid of a metal vapor vacuum are(MEVVA)ion source.The blender of Nd5Si4 and NdSi2 was formed in a neodymium-implanted silicon thin film during the as-implanted state,but there was only single neodymium silicide compound in the post-annealed state,and the phase changed from NdSi2 to Nd5Si4 with increasing annealing temperature.The blue-violet luminescence excited by ultra-viloet was observed at the room temperature(RT),and the intensity of photoluminescence(PL)increased with increasing the neodymium ion fluence,Moreover,the photoluminescence was closely dependent on the temperature of rapid thermal annealing(RTA),A mechanism of photoluminescence was discussed.     

离子注入精密摩擦付的橡拟实验研究

精密摩擦付是每种具有转动或滑动动作的精密机械的关键零件。从使用的角度来看,它的质量直接决定着整机的技术指标。制造经久耐用的精密摩擦付对于提高整机性能有二重意义:其一,长寿命摩擦付自然延长整机的使用寿命,减少零件耗损与整机维修时间,有很大的经济意义;其二,对于特定的使用场合,机器一经启动,在相当长的时间内不可停机,长寿命精密摩擦付就更加显示出其重要性了。从制造的角度来看,精密摩擦付允许公差很小,只有     

Nanoscratch study of ZnO thin films deposited using radio frequency magnetron sputtering

In this study, a radio frequency magnetron sputtering system was used to deposit zinc oxide (ZnO) thin films onto langasite substrates. The thickness of the ZnO film increased from 0.3 to 1.2 μm upon increasing the deposition power from 100 to 200 W. The predominant growth orientation was along the c-axis (0 0 2); the intensities of the signals in the X-ray diffraction spectrum increased significantly upon increasing the film thickness. Scanning electron microscopy images revealed columnar structures in the ZnO films and the morphology of ZnO grains is found to be continuous and dense. It is attributed that oxygen chemisorbs on the target and cases a surface layer of adsorbed oxygen. We suggest that the more neutral ion bombardment on the growing film which induces the higher sputtering rate of the growing film. From in situ imaging of scratched tracks, measurement of the coefficient of friction was an effective means of detecting the occurrence of structural defects in the microstructures. We also found that the chemical compositions of ZnO films prepared under various deposition powers could be investigated using X-ray photoelectron spectroscopy.     

The solid film lubrication by carbon ion implantation into α-Al2O3

Improvement in tribological performance by C⁺110 keV implantation can be achieved by having a more graphite-like carbon structure on Al₂O₃. It was shown that fracture toughness and critical peeling load increased for a fluence of 5 × 10¹⁷C⁺/cm² because of residual compression stress and amorphism of surface. The testing in a different implantation dose indicated that the friction and wear mechanism in Optimol fretting wear machine (SRV) was a combination of surface structure and its abrasive wear. Raman shift shows that the amorphous graphite with 5 × 10¹⁷–1 × 10¹⁸ C⁺/cm² implantation dose was formed on Al₂O₃ surface, so that it reduced friction coefficient and wear of Al₂O₃, also it is noticed that the failure of lubrication due to graphite-like film wear is much earlier in the implantation sample with 1 × 10¹⁷C⁺/cm² dose.     

Influence of Cr-ions on the magnetic behaviour of FeCo film

Implantation of Cr-ions in Fe₇₀Co₃₀ thin film have been performed to modify its structural and magnetic properties. From the XRD results, the lattice constant as well as the grain size of the film is increasing with the ion fluence. Cr-ions (1 × 10¹⁷ ions/cm²) reduces the coercivity of the film from 140(3) Oe to 44(3) Oe. Coercivity of the film follows the exponential decay as a function of Cr-ions fluence. 35 keV (projectile range 13.5 nm) and 100 keV Cr-ions (projectile range 34.3 nm) have been used to understand the effects of magnetic Cr-ions and the effects of ballistic collision cascade on the MOKE signal. Similar changes on the coercivity behaviour of the film implanted with these two energies have been observed. It appears that the implantation process creates a solid solution of Cr in FeCo without any other additional treatment in the film. After 5 × 10¹⁶ Cr-ions, film exhibit four fold magnetic anisotropy.     

Structural and compositional characterization of LiNbO3 crystals implanted with high energy iron ions

Iron ions were implanted with a total fluence of 6 × 10¹⁷ ions/m² into lithium niobate crystals by way of a sequential implantation at different energies of 95, 100 and 105 MeV respectively through an energy retarder Fe foil to get a uniform Fe doping of about few microns from the surface. The implanted crystals were then annealed in air in the range 200-400 °C for different durations to promote the crystalline quality that was damaged by implantation. In order to understand the basic phenomena underlying the implantation process, compositional in-depth profiles obtained by the secondary ion mass spectrometry were correlated to the structural properties of the implanted region measured by the high resolution X-ray diffraction depending on the process parameters. The optimised preparation conditions are outlined in order to recover the crystalline quality, essential for integrated photorefractive applications.     

Wear mechanism and microstructures of Mo-implanted 4Cr5MoV1Si steel

tance and microstructure of implanted specimen were1 Introduction discussed according to the results of RBS, GXRD and The influence of pulsed beam in ion implantation XPS.is a topic of interest in both ion beam modification 2 Experimentaland radiation effect research.[1-3] Currently, a majorapplication of ion implantation is to improve the cor- Square steel samples (0.36wt.%…     

Ta离子注入Ti6Al4V合金的抗腐蚀性能

用注量为1.2×1016、3×1016、1.5×1017、3×1017、4.5×1017/cm2的Ta离子对Ti6Al4V合金进行表面改性,加速电压为146.5 keV。Ta离子注入后,用动电位极化曲线研究其抗Hank’s溶液腐蚀性能,用小角掠射X射线衍射研究其表面物相结构,用X射线光电子能谱分析其腐蚀样品的表面元素化合态。结果表明,Ta离子注入改善了Ti6Al4V合金抗Hank’s溶液腐蚀性能,但试样的腐蚀电流密度并非随Ta离子注量增加而单调减小,试样表面合金层、单质Ta和氧化物,共同形成腐蚀阻挡层,提高其抗腐蚀性能。