~(75)A_S~ 离子注入的AI_2O_3膜抗腐蚀性的研究

本文研究了用~(75)A_s~ 离子注入的Al_2O_3膜的抗腐蚀性。Al_2O_3膜在磷酸中的最小腐蚀速率(或最佳的~(75)A_s~ 杂质浓度)能根据实验结果和类高斯离子射程分布得到。实验结果表明,注入离子的Al_2O_3膜在H_3PO_4—CrO_3溶液中的腐蚀率要比未注入的Al_2O_3膜在相同条件下的腐蚀速率小10倍以上。因此,甚至在酸中,离子注入在改善材料表面层的抗腐蚀性方面也是有希望的技术。     

Z1- AND Z2-OSCILLATIONS OF ELECTRONIC STOPPING CROSS SECTIONS OBTAINED BY SHELL-WISE CALCULATION AND HARMONIC-OSCILLATOR MODEL

A shell-wise calculation method and a quantal harmonic-oscillator model have been used to calculate the electronic stopping cross sections for heavy ions colliding with atoms or penetrating matter. The electronic energy loss is given in an impact parameter formalism. In order to generalize the theoretical models, which pertain to the cese of point charge interacting with matter, to the case for heavy ions, an effective stopping charge hased on the modified BK theory is used by way of simple scaling in the calculations. The comparisons between the calculated results and the experimental data demonstrate a favourable evidence to justify the theoretical models.     

SnO_2(F)、Fe_2O_3和ZnSe(Fe)薄膜厚度的测量

用RBS技术、椭偏法和微量天平称重法测量了掺氟SnO_2(FTO)透明导电膜、掺铁ZnSe磁性半导体膜和Fe_2O_3气敏元件膜的薄膜厚度.实验结果表明,RBS技术的测量数值与椭偏法以及微量天平称重法测得的结果符合得较好。     

惰性气体氙(Xe)在不锈钢中的扩散和释放

采用2Mev~4He~ 离子的卢瑟福背散射技术详细地研究了Xe在不锈钢中的扩散和释放过程,不锈钢衬底中的Xe是由离子注入引入的,注入的能量为30Kev,~(129)Xe~ 离子的剂量为2.8×10~(15)ions/cm~2。恒时退火累积分数释放额的测量表明,Xe在不锈钢中的迁移和释放可分为三个阶段。实验发现经Xe离子注入的不锈钢样品表面极易氧化,在退火温度为488℃——789℃的范围内,表面层的氧化将驱使Xe向衬底内部迁移。     

离子注入Al0.25Ga0.75As/GaAs的Raman光谱研究

0.8 MeV的Si离子注入Al_0.25Ga_0.75As/GaAs外延薄膜的弱损伤特征.注入剂量从1×10¹⁴～5×10¹⁵ cm^-2,对注入后的样品采用了Raman光谱测量,观察到了两类声子模式,该外延材料的晶格振动显示出“双模”行为.并计算了在注入层中的应变以及晶格常数随剂量的变化.此外还测量了样品的Rutherford背散射和沟道谱(RBS/C),结果表明与Raman光谱测量一致的结论：该注入条件只引起材料的弱损伤行为.     

生物厚靶的He+离子透射能谱

测量了５００ ｋｅ Ｖ—１ Ｍｅ Ｖ 的 Ｈｅ ＋ 离子穿过５０ —９０ μｍ 厚度的玉米种皮、葡萄果皮和西红柿果皮的透射能谱．结果表明这些生物厚靶是不均匀的,存在着类似于“沟道”的开放通道,沿着这些通道入射离子可以容易地透过靶材料．虽然大多数离子停留在靶中,但一部分透射离子只损失很少的能量．透射能谱显示出一种纯粹的电子阻止特征．３０ μｍ 厚度样品的透射电子显微镜图谱（ Ｔ Ｅ Ｍ） 显示１５０ ｋｅ Ｖ 的电子可以穿过这些样品得到很清晰的图象．β１ ,４ 葡聚糖是生物种皮或果皮细胞壁的重要的组成部分,计算了该分子链的电子结构,指出了生物样品中可能存在的通道方向．     

铯在铝中扩散的研究

详细地研究了铯在铝中的扩散和释放过程。铝衬底中的铯是由离子注入引入的。采用2MeV~4He~ 离子的卢瑟福背散射技术测量铝衬底中铯浓度的深度分布。通过分析恒时退火过程中铯在铝中的迁移和从表面释放的资料,得到了铯在铝中的扩散系数。实验表明,铯在单晶和多晶铝中有十分类似的扩散行为。铯离子注入剂量N_d(?)6×10~(16)ionscm~(-2)的情况下,铯在铝中的扩散系数随温度的变化可表示为D(?)0.02exp(-46000/RT)cm~2·sec~(-1).而在剂量较底的情况下(N_d(?)10~(16)ions cm~(-2)),可表示为D(?)0.02exp(-44000/RT)cm~2·sec.~(-1)。实验证实了永久性的强陷阱中心的存在。     

Monte Carlo Simulation on Energy Deposition of Low-Energy Electrons in Liquid Water

A Monte Carlo approach to simulate the transport and energy deposition of low energy electrons (E0≤10keV) in liquid water is presented. The elastic scattering of electrons is described by Mott cross section, which is derived from the relativistic wave equation of Dirac. The inelastic scattering model of electrons is based on the dielectric response theory with exchange effect included. A new method of sampling various inelastic scattering events is proposed in the simulation. Using the approach stated, the spatial distribution of inelastic scattering events and energy deposition of electrons in liquid water are computed and the results are compared with other theoretical studies.     

Proton Inelastic Mean Free Path in a Group of Organic Materials in 0.05-10MeV Range

Inelastic mean free paths （MFPs） of 0.05-10 MeV protons in a group of 10 organic compounds are systematically calculated. The calculations are based on the method newly derived from the Ashley optical-data model and from the higher-order correction terms in stopping power calculations. Especially, in this method the new and empirical Bloch correction for the inelastic MFP is given. An evaluation for the optical energy loss function is incorporated into the present calculations because of the lack of available experimental optical data for the considered organic compounds expect for kapton. The proton inelastic MFPs for these 10 organic compounds in the energy range from 0.05 to 10 MeV are presented here for the first time, and the combination of these inelastic MFP data and our previous data of stopping power calculation for these bioorganic compounds may form a useful database for Monte Carlo track-structure studies of various radiation effects on these materials.     

生物厚靶的He+离子透射能谱

测量了500keV—1MeV的He⁺离子穿过50—90μm厚度的玉米种皮、葡萄果皮和西红柿果皮的透射能谱．结果表明这些生物厚靶是不均匀的,存在着类似于“沟道”的开放通道,沿着这些通道入射离子可以容易地透过靶材料．虽然大多数离子停留在靶中,但一部分透射离子只损失很少的能量．透射能谱显示出一种纯粹的电子阻止特征．30μm厚度样品的透射电子显微镜图谱(TEM)显示150keV的电子可以穿过这些样品得到很清晰的图象．β-1,4葡聚糖是生物种皮或果皮细胞壁的重要的组成部分,计算了该分子链的电子