150keV Ar离子辐照非晶态合金表面发泡和溅射形貌研究

150keV Ar离子辐照非晶态合金Fe₃₉Ni₃₉Mo₂Si₁₂B₈、Fe₄₀Ni₄₀Si₁₂B₈、Fe₃₉Ni₃₉V₂Si₁₂B₈、Fe₇₇Cr₂Si₅B₁₆和Fe₇₈Si₁₀B₁₂,用扫描电子显微镜(SEM)观测研究了表面损伤形貌剂量变化的过程.低剂量时表面发泡形成.发泡随剂量增加受到溅射腐蚀,表面形成坑洞或针孔,针孔密度随剂量增加而增加,高剂量时,表面损伤以溅射为主,溅射对表面的腐蚀导致多孔粗糙的表面损伤结构建立,并且这些结构与靶材料有着密切的关系.     

国产高Z闪烁晶体的辐照损伤研究

在总强度为10⁵Ci^的60Co γ射线辐照装置上开展了国产高Z闪烁晶体的辐照损伤研究.在5×10³—7.5×10⁵rad剂量范围内测量了小尺寸BGO晶体样品的辐照损伤效应,观察到损伤随剂量增加逐渐趋于饱和的现象;辐照损伤的自然恢复过程可用三组时间常数表征的指数函数描述.在5×10⁵rad剂量下,考察了BaF₂,CsI(Tl)以及ZnWO₄晶体小尺寸样品的辐照损伤效应.发现了BaF₂的严重损伤情况,初步分析原因可能是晶体中某些微量杂质的存在.     

强脉冲X射线辐照在Si-SiO2中感生的界面态及退火消除

 利用强脉冲X射线对Si-SiO₂界面进行了辐照，测量了界面态曲线和退火曲线。实验显示，经过强脉冲X射线对Si-SiO₂界面进行的辐照，在Si-SiO₂界面感生出新的界面态，感生界面态的增加与辐照剂量成正比，并且易出现饱和现象。总结出了感生界面态密度产额Dit随辐照剂量D变化的分布式，并定性分析了Dit随D变化的行为。随后进行的退火实验表明，强脉冲X射线辐照感生出的界面态越多，退火时这些界面态就消除得越快。退火过程显示有滞后现象，即辐照剂量大的阈电压漂移，在退火后恢复的绝对值，要小于辐照剂量小的阈电压漂移。导出了阈电压漂移随退火时间变化的关系，定性解释了滞后现象。     

质子辐照空间级硅橡胶的正电子淹没寿命谱研究

 用正电子淹没寿命谱方法（PALS）研究了质子辐照对空间级硅橡胶KH-L-Y微观结构的影响。试验结果表明，PALS谱所揭示的最长寿命成分的t₃, I₃及自由体积分数Vf随辐照剂量的增加开始明显下降；而当辐照剂量大于10¹⁵cm^-2后，随剂量的增加平缓上升。辐照剂量小于10¹⁵cm^-2时，质子辐照使硅橡胶自由体积减小，分子链间堆砌紧密；辐照剂量大于10¹⁵cm^-2时，质子辐照使硅橡胶自由体积增大。交联密度及DMA测试结果同样表明，质子辐照在剂量较小时硅橡胶的交联密度及玻璃化转变温度增加，辐照以交联效应为主；而剂量较大时辐照降解占优势。     

高纯硅低能粒子辐照E′色心形成动力学研究

考虑固有点缺陷形成E′色心的情况，建立了E′色心形成的动力学模型，得到了高纯硅低能粒子辐照E′色心浓度与辐照剂量的关系式.结果表明，在低辐照剂量下，E′色心浓度随剂量的变化呈线性增长；随着辐照剂量的增加，E′色心浓度随剂量的变化呈饱和趋势.如果进一步考虑E′色心和其他物质反应形成新的稳定结构，E′色心浓度随剂量的变化呈双指数关系，E′色心浓度随剂量的变化不再趋于饱和状态，而是偏离饱和状态.理论结果和实验结果很好地符合，说明建立的模型是有效的.     

钨酸铅晶体的辐照损伤研究

报道对钨酸铅晶体作低剂量辐照损伤研究的实验装置、方法、和结果.利用北京计量科学研究院的小型⁶⁰Co放射源对4块钨酸铅晶体作了辐照损伤的实验,发现光产额随辐照剂量的增加呈现指数衰减,最后趋于饱和.     

He+辐照对Ga0.94Mn0.06As薄膜铁磁性的改善

离子辐照半导体可以很好的改善半导体材料的磁学性质.用He⁺ 辐照Ga_0.94Mn_0.06As薄膜,可以较方便的调制Ga_0.94Mn_0.06As 薄膜中产生铁磁性载体的浓度.由于空穴居间而导致Ga_0.94Mn_0.06As薄膜的铁磁性, 可以通过He⁺的辐照来得到改善,其结果是Ga_0.94Mn_0.06As薄膜的矫顽力可以增加3倍多. 当He⁺辐照流强增加时, 居里温度和沿着样品面外磁化难轴方向的饱和磁场都减小了. 被辐照的Ga_0.94Mn_0.06As薄膜的电学性质和结构特征显示, He⁺辐照Ga_0.94Mn_0.06As薄膜可以有控制地改善它的铁磁性, 其结果源于He⁺辐照Ga_0.94Mn_0.06As薄膜所诱导产生电缺陷对空穴的补偿, 而不是He⁺辐照改变了Ga_0.94Mn_0.06As薄膜的结构.     

氧离子辐照二氧化钛单晶后的结构与磁性

氧离子辐照二氧化钛单晶可以诱发其铁磁性．辐照后在室温下也能观察到二氧化钛的铁磁性,且对温度依赖性较小．结合X射线衍射实验、卢瑟福背散射/沟道实验、拉曼散射实验谱、电子自旋共振实验谱、超导量子干涉仪实验、单位原子随沟道位移实验,测定了晶格的损伤随辐照流强的增加而增加．发现在氧离子辐照二氧化钛时出现了Ti³⁺替代氧空位(O_V)的缺陷复合体,即形成Ti³⁺-OV复合体．这种缺陷复合体导致了局部(TiO_6-x)的拉曼模式的伸展．说明了Ti³⁺结合一个未成对的3d电子是二氧化钛局部铁磁性的起源.     

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     

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.     

Effects of silicon negative ion implantation in semi-insulating gallium arsenide

ABSTRACT

In the present work, effects of silicon negative ion implantation into semi-insulating gallium arsenide (GaAs) samples with fluences varying between 1?×?10¹⁵ and 4?×?10¹⁷?ions?cm^?2 at 100?keV have been described. Atomic force microscopic images obtained from samples implanted with fluence up to 1?×?10¹⁷?ion?cm^?2 showed the formation of GaAs clusters on the surface of the sample. The shape, size and density of these clusters were found to depend on ion fluence. Whereas sample implanted at higher fluence of 4?×?10¹⁷?ions?cm^?2 showed bump of arbitrary shapes due to cumulative effect of multiple silicon ion impact with GaAs on the same place. GXRD study revealed formation of silicon crystallites in the gallium arsenide sample after implantation. The silicon crystallite size estimated from the full width at half maxima of silicon (111) XRD peak using Debye-Scherrer formula was found to vary between 1.72 and 1.87?nm with respect to ion fluence. Hall measurement revealed the formation of n-type layer in gallium arsenide samples. The current–voltage measurement of the sample implanted with different fluences exhibited the diode like behavior.     

Structure and properties of molybdenum implanted with high-flux carbon ion

High purity molybdenum was implanted by C ion in a metal vapour vacuum arc (MEVVA) implanter. The influence of implantation parameters was studied by varying ion fluence and ion current density. The samples were implanted by 45 keV C ion with fluences from 1×10¹⁵ to 1×10¹⁸ ions/cm², respectively. The as-implanted samples were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and nanoindenter. Different morphologies were observed on the surfaces of the as-implanted samples due to irradiation damage, and clearly related to implantation parameters. XRD spectra confirm formation of β-Mo₂C with ion fluences equal to or larger than 1×10¹⁶ ions/cm², and formation of -Mo₂C with ion fluence of 1×10¹⁸ ions/cm². The maximum nanohardness and maximum modulus of the as-implanted samples increased gradually with increasing ion fluence, and reached the corresponding maximum values with ion fluence of 1×10¹⁸ ions/cm². The experimental results suggest that the structure and properties of the as-implanted Mo samples exhibited strong dependence on implantation parameters.     

RBS and TEM studies of indium phosphide irradiated with 100 keV Au ions

Transmission Electron Microscopy (TEM) and Rutherford Backscattering (RBS) have been used to observe the spatially isolated disordered zones in InP resulting from 100 keV Au ion irradiation at room temperature. Studies were carried out in interval of irradiation fluences less than lower value of full amorphization fluence. Such a value of fluence, as was established in the studies, can be estimated of order ∼2.5 × 10¹³cm⁻². The accumulation of damage due to the 100 keV Au ion irradiation was described in this material using a composite theoretical model accounting for both homogeneous and heterogeneous amorphization processes.     

Step edge sputtering yield at grazing incidence ion bombardment

The surface morphology of Pt(111) was investigated by scanning tunneling microscopy after 5 keV Ar+ ion bombardment at grazing incidence in dependence of the ion fluence and in the temperature range between 625 and 720 K. The average erosion rate was found to be strongly dependent on the ion fluence and the substrate temperature during bombardment. This dependence is traced back to the variation of step concentration with temperature and fluence. We develop a simple model allowing us to determine separately the constant sputtering yields for terraces and for impact area stripes in front of ascending steps. The experimentally determined yield of these stripes--the step-edge sputtering yield--is in excellent agreement with our molecular dynamics simulations performed for the experimental situation.     

Comparative study on low energy ion beam modification of thermoplastic polymers

ABSTRACT

Polycarbonate (PC) and polyethylene terephthalate (PET) thermoplastic polymer films were irradiated by low energy ion beams such as 100 keV Hydrogen (H⁺) ions and 350 keV Nitrogen (N⁺) ions at varied fluence from 1?×?10¹³ ions/cm² to 5?×?10¹⁴ ions/cm². The depth profile concentration of ions was calculated using Stopping and Range of Ions in Matter (SRIM) software code. Fourier Transform Infrared (FTIR) technique shows decrement in the intensity of peaks and disappearance of peaks mainly related to carbonyl stretching at 1770?cm^?1 and C–C stretching at 1500?cm^?1. Scanning electron microscopy (SEM) of irradiated polymers showed the formation of pores. X-ray diffraction (XRD) analysis has showed decrease in the intensity indicating the decrease in crystallinity after irradiation. Mechanical studies revealed that the molecular weight and microhardness decrease with increase in ion fluence due to increase in chain scission. The contact angle increased with increase in ion fluence indicating the hydrophobic nature of polymer after irradiation. Antibiofilm activity test of irradiated films shows resistance to Salmonella typhi (S. typhi) pathogen responsible for typhoid. The study shows that Nitrogen ion induces more damage compared to Hydrogen ions and PC films get more modified than PET films.     

Integral and temporal characteristics of soft X-rays of the PF-4 plasma focus setup

Soft X-rays of a setup with a power from 1.5 to 5 kJ, operating with argon, were measured using X-ray pinhole cameras and SPPD 11-04 detectors. Integral measurements of X-rays in energy ranges above 1.2, 1.5, 1.8, and 2.5 keV were performed using a 4-frame pinhole camera with hole sizes of ～250 µm. Simultaneously, the X-ray yield was measured with time resolution in the energy region of > 1.8 keV using a semiconductor detector. X-ray characteristics were experimentally studied at a capacitor bank voltage of 8–14 kV and argon pressures from 1.2 to 3 Torr. The size of hot points was estimated using the pinhole camera with a hole size of ～20 µm as less than 13–25 µm.     

Co+离子注入单晶TiO2铁磁性来源与微结构研究

在室温下,将能量为80 keV, 注量分别为1×1016和1×1017ions/cm2的Co+离子注入到10 mm×10 mm×0.5 mm的单晶TiO₂样品。在氮气保护下, Co+离子注量为1×1017 ions/cm2时样品在温度为900 ℃的条件下退火30 min。 利用超导量子干涉仪 （SQUID）测量样品磁性, 并应用X射线衍射（XRD）和扩展边X射线吸收精细结构谱（EXAFS）研究Co+离子注入后样品的微观结构。 样品磁性测量结果表明:Co+离子注入后的样品具有室温铁磁性, 并且其饱和磁化强度的大小与Co+离子注量及样品是否经退火处理有关。 EXAFS研究表明: Co元素在Co+离子注量为1×1017ions/cm2的样品中主要以团簇形式存在;样品经退火处理后, Co团簇消失, 并发现Co部分替代TiO₂单晶中的Ti。Co+离子注入后, 在样品中形成Co团簇与否受离子注量的影响。 阐述了样品微观结构与铁磁性来源之间的关系。 At room temperature, monocrystalline plates of rutile (TiO₂) were implanted with cobalt ions of an energy of 80 keV to fluences of 1×1016 and 1×1017 ions/cm2 respectively . The 1×1017 ions/cm2 Co implanted samples were annealed in nitrogen at 900 ℃ for 30 min. The magnetic properties of Co implanted samples were measured with a superconducting quantum interference device magnetometer (SQUID) at room temperature. Furthermore, the X ray diffraction (XRD) and Extended X ray Absorption Fine Structure (EXAFS) were applied to investigate the structural and compositional properties of Co implanted samples. The magnetic measurements of samples showed that the size of the saturation magnetization of the Co implanted samples were related to the fluence of ions, and the saturation magnetization of the sample after annealed decreased significantly. The EXAFS measurements showed the presence of cobalt metallic clusters in the sample implanted to ion fluence of 1×1017 ions/cm2. The Co metallic clusters disappeared in the sample after annealed, and resulted in the oxidized Co, which is presumed to substitute into the Ti site. The formation of Co clusters or not was determined by the ion fluence. The relation between ferromagnetic behavior and microscopic structure of the Co implanted samples is discussed.     

气体团簇离子束两步能量修形法的平坦化效应

本文提出采用气体团簇离子束的两步能量修形法来改善4H-SiC(1000)晶片表面形貌.先用15 keV的高能Ar团簇离子进行整体修形,再用5 keV的低能团簇离子优化表面.结果表明,在相同的团簇离子剂量下,与单一15 keV的高能团簇处理相比,两步法修形后的表面具有更低的均方根粗糙度,两者分别为1.05 nm和0.78 nm.本文还以原子级平坦表面为研究对象,揭示了载能团簇引起的半球形离子损伤(弧坑)与团簇能量的关系,及两步能量修形法在弧坑修复中的优势.在原子力显微镜表征的基础上,引入了二维功率谱密度函数,以直观全面地给出材料的表面形貌特征及其随波长(频率)的分布.结果表明,经任何能量的团簇离子轰击的表面,在0.05—0.20μm波长范围内,团簇轰击都能有效地降低粗糙度,而在0.02—0.05μm范围内,则出现了粗化效应,这是由于形成了半球形离子损伤,但第二步更低能量的团簇离子处理可以削弱这种粗化效应.     

Ion track effect on point defect production in SiC

Low-temperature (40 K) photoluminescence (PL) measurements were used to follow the defect formation induced in the 4H-SiC epitaxial layer by irradiation with 200 keV H⁺ and 800 keV C⁺ in the fluence range of 5×10⁹–3.5×10¹² ions/cm². After irradiation, the PL spectra show the formation of some sharp lines, called “alphabet lines”, located in the wavelength range of 425–443 nm, due to the recombination of excitons at structural defects induced by ion beams. The analysis of luminescence line intensity versus ion fluence allows us to mark two different groups of peaks, namely the P1 group (e, f and g lines) and the P2 group (a, b, c and d lines). The normalised yield of P1 group lines increases with ion fluence and reaches a maximum value, while the normalised yield of P2 group lines exhibits a threshold fluence and then increases until a saturation value is reached. These different trends indicate that, while the P1 group lines are related to the primary defects created by ion beams (interstitial defects, vacancies), the P2 group lines can be associated with some complex defects (divacancy, antisites). The trends are similar for irradiation with H⁺ and C⁺ ions; however, the defect formation occurs in the fluence range of 5×10⁹–10¹¹ ions/cm² for C⁺ irradiation and 10¹¹–4×10¹² ions/cm² for H⁺ irradiation. Taking into account the different values of energy deposited in elastic collision, a dependence on the ion type was found: the C⁺ ion results in being less effective in defect production as a higher defect recombination occurs inside its dense cascade.     

Mechanism of defect evolution in H+ and He+ implanted InP

The defect evolution in InP with the 75 keV H⁺ and 115 keV He⁺ implantation at room temperature after subsequent annealing has been investigated in detail. With the same ion implantation fluence, the He⁺ implantation caused much broader damage distribution accompanied by much higher out-of-plane strain with respect to the H⁺ implanted InP. After annealing, the H⁺ implanted InP did not show any blistering or exfoliation on the surface even at the high fluence and the H₂ molecules were stored in the heterogeneously oriented platelet defects. However, the He molecules were stored into the large bubbles which relaxed toward the free surface, creating blisters at the high fluence.