Enhancement of ZnO thin film transistor performance by high-dose proton irradiation

The object of this study was to improve the performance of ZnO thin film transistors (TFTs) by exposing them to high-dose proton irradiation. A rapid thermal annealing (RTA) process was necessary to improve the interface characteristics between the source-drain electrodes and the channel layer for the high performance of ZnO-TFTs. However, this affected the resistivity of the ZnO channel layer; it was dramatically decreased during the RTA process. As a result, the RTA-treated ZnO-TFTs did not show the proper off-state characteristics. In order to control the electrical properties of the channel layer, we exposed the RTA-treated ZnO-TFTs to 6.1 MeV of proton irradiation beam energy at fluences from 6.7 × 10¹² cm⁻² to 6.5 × 10¹⁴ protons-cm⁻². The resulting resistivity of the ZnO thin film increased after the high-dose proton irradiation. In addition, we studied the structural and electrical properties and the variations in the native defects of ZnO thin films. The field effective mobility of ZnO-TFTs increased from 1.65 to 4.12 cm²/V s after both the RTA and the high-dose proton irradiation. We obtained an enhancement of ZnO-TFT performance using high-dose proton irradiation.     

0.28-2.80 MeV质子辐射对空间实用GaInP/GaAs/Ge多结太阳电池性能的影响

用0.28、0.62和2.80 MeV质子束模拟空间辐射对国产MOCVD方法制备的GaInP/GaAs/Ge多结电池进行质子辐射效应研究.辐照注量为1×1012 cm-2.对电池的辐射效应用I-V特性和光谱响应测试进行分析.结果表明:随质子辐照能量的增加,太阳电池性能参数Isc,Voc,Pmax和光谱响应的衰降幅度均减小,0.28MeV质子辐照引起电池性能衰降最显著;低能质子辐照引起中间GaAs电池光谱响应衰降更明显.     

50-170 keV质子照射对GaAs/Ge太阳能电池光谱响应的影响

用固定能量(100 keV)不同注量(1×1011-3×1012 cm-2)或固定注量(3×1012 cm-2)不同能量(50-170 keV)的质子,照射GaAs/Ge太阳电池,获得材料的光谱响应特性随质子能量和注量的变化关系.结果表明,质子辐照对材料的光学性能有破坏性的影响.这种破坏性源于质子辐照引入的大量缺陷,使晶格空间的完整性受到破坏,导致少子的扩散长度降低、表面复合速度增加.在质子能量相同的条件下,电池光学性能衰降随照射注量增大;在注量相同的条件下,辐射能量越高,太阳电池光学性能衰降越大.     

高能Ar离子辐照PET膜引起的表面改性研究

采用傅立叶转换的红外光吸收技术在反射方式下分析研究了35MeV/u Ar离子辐照半晶质PET膜引起的表面改性及其对吸收剂量的依赖性。结果表明,辐照导致PET膜中与晶态区域相关的吸收带强度随吸收剂量增加普遍减弱,而与非晶区域相关的吸收带强度随吸收剂量增加逐渐增加,表明辐照使PET膜发生了非晶化转变。化学键断裂主要发生在苯环的对位和酯的C－O键上,而苯环的基本结构在整个辐照过程中变化较小。非晶化效应和化学键断裂同时依赖于离子的照射剂量和样品表面的电子能量沉积。此外,在约5．0MGy以上的吸收剂量,辐照还引起了炔端基团的形成,炔端基团浓度随吸收剂量的增加显著增加。对实验结果进行了定性解释。     

利用粒子辐照技术实现碳纳米管向金刚石的转变

采用低能氢等离子体和中能C^ 离子束辐照技术相结合的方法,实现了碳纳米管向金刚石纳米晶粒的转变,完成了一个从有序(碳纳米管)到无序(无定形碳纳米线)再到有序(金刚石纳米晶)的转变过程。利用透射电子显微镜(TEM)、选区电子衍射(SAD)和拉曼光谱(Raman)等研究了晶粒的微观结构,并对纳米金刚石晶粒的生成机理进行了初步探讨。     

辐射法制备含氟磺酸型质子交换膜

含氟磺酸型质子交换膜是一类具有高热稳定性、化学稳定性及良好机械性能的离子交换膜，具有极其广阔的应用前景。采用辐射法制备了一种含氟磺酸型质子交换膜，分别测试了该膜的抗拉强度、面电阻、吸碱率等物理化学性能，通过扫描电镜观察了其表面形貌并对其在质子交换膜燃料电池中的应用进行了初步研究。     

Erosion of carbon fiber composites under high-fluence heavy ion irradiation

The ion-induced erosion, determining by sputtering yield Y and surface evolution including structure and morphology changes of the modified surface layers, of two commercial carbon fiber composites (CFC) with different reinforcement - KUP-VM (1D) and Desna 4 (4D) have been studied under 30 keV Ar⁺ high fluence (φt ∼ 10¹⁸-10²⁰ ion/cm²) irradiation in the temperature range from room temperature to 400 °C. Ion-induced erosion results in the changes of carbon fiber structure which depend on temperature and ion fluence. Monitoring of ion-induced structural changes using the temperature dependence of ion-induced electron emission yield has shown that for Desna 4 and KUP-VM at dynamic annealing temperature Т_а ≈ 170 °С the transition takes place from disordering at T < T_a to recrystallization at T > T_a. The annealing temperature Т_а is close to the one for polycrystalline graphites. Microscopy analysis has shown that at temperatures Т < T_a the etching of the fibers results in a formation of trough-like longitudinal cavities and hillocks. Irradiation at temperatures T > T_a leads to a crimped structure with the ribs perpendicular to fiber axis. After further sputtering of the crimps the fiber morphology is transformed to an isotropic globular structure. As a result the sputtering yield decreases for Desna 4 more than twice. This value is almost equal to that for KUP-VM, Desna 4, polycrystalline graphites and glassy carbons at room temperature.     

Adjusted NIEL calculations for estimating proton-induced degradation of GaInP/GaAs/Ge space solar cells

The non-ionizing energy loss (NIEL) values for protons in solar cells should be modified by taking into account the distribution of the Bragg damage peak in the active region to calculate the corresponding displacement damage dose. In this paper, based upon a thin target approximation, a new approach is presented to modify NIEL values for protons on a GaAs sub-cell. Adjusted NIEL values can be used to estimate the degradation induced by protons on GaInP/GaAs/Ge triple-junction space solar cells.     

炭/炭复合材料对活化片辐照的影响

根据钍基熔盐堆高温环境辐射测量需求,采用具有高温抗氧化Si C涂层的炭/炭复合材料作为待测活化片的载体材料,介绍了采用炭/炭复合材料作为辐照载体的优越性,对其进行了成分和热分析测试,并详细描述了带有炭/炭复合材料的一组活化片和不带有炭/炭复合材料的另一组活化片同时在铀氢锆脉冲堆的径向实验孔道中进行中子辐照的实验过程。通过比较两组活化片的单核反应率,详细分析了炭/炭复合材料对活化片辐照结果的影响。结果表明,载体采用涂层为Si C的炭/炭复合材料,并且壁厚为几个毫米时,对多种活化片的中子辐照结果影响很小,可以作为高温环境下辐照材料的载体。     

Structural and optical study of irradiation effect in GaN epilayers induced by 308 MeV Xe ions

Wurtzite GaN epilayers irradiated at room temperature with 308 MeV ¹²⁹Xe³⁵⁺ ions to fluences of 1 × 10¹³ and 3 × 10¹³ cm⁻² have been studied by contact mode atomic force microscopy (AFM), high-resolution X-ray diffraction (HRXRD), micro-Raman scattering and photoluminescence (PL) spectroscopy. The AFM images showed that the surface of GaN films was etched efficiently due to the Xe ion irradiation. The initial step-terrace structure on GaN surface was eliminated completely at a fluence of 3 × 10¹³ cm⁻². HRXRD and Raman results indicated that the Xe ion irradiation led to a homogenous lattice expansion throughout the entire ∼3 μm-thick GaN films. The lattice expansion as well as the biaxial compressive stress of the films was increasing with the increase of ion fluence. PL measurements showed that a dominant yellow luminescence band in the as-grown GaN films disappeared, but a blue and a green luminescence bands were produced after irradiation. Based on these results, the strong electronic excitation effect of 308 MeV Xe ions in GaN is discussed.     

Effect of carbon black on the properties of irradiated recycled polyamide/rubber waste composites

In the present study, the synergistic effect of carbon black (CB) content % and gamma irradiation on some mechanical, thermal, chemical stability and micro-structural properties of the moulded waste polyamide copolymer/recycled waste rubber powder (rPA/WRP) 50/50 was investigated. The ternary composites of CB concentrations, 6, 12, 18, and 24 wt.%, were irradiated with doses of 50, 100, 150 and 200 kGy. The composites mechanical properties: tensile strength, elongation at break, and hardness, and the thermal properties: melting temperature (T_m) and (ΔH) were measured. Also, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), swelling and chemical stability were investigated.     

Monte Carlo study of molecular weight distribution changes induced by degradation of ion beam irradiated polymers

In this work we study a polymeric material that degrades upon irradiation due to the energy inhomogeneously deposited by heavy ion beams. Ion beam irradiation of polymers generates rather different effects than those induced by “classical” low ionizing particles such as electrons or gamma rays. This is due to the high electronic stopping power and the inhomogeneous distribution of deposited energy. This energy is transferred to the material within a small volume along the ion path forming the so called “nuclear track” or “latent track”. The track size primarily depends on the ion velocity, and it is determined by the secondary electrons (delta rays) generated along the ion trajectory. By means of Monte Carlo simulations we first obtained equilibrated polymer configurations using a coarse-grained model, and then investigated the spatially inhomogeneous chain scission process due to the passage of the ions. The number average molecular weight, weight average molecular weight and the polydispersity were calculated as a function of track radius, scission probability within the ion track and irradiation fluence. Finally we compared our results with a numerical implementation of a model for random homogeneous degradation.     

Effect of high temperature annealing on ferromagnetism induced by energetic ion irradiation in FeRh alloy

Effects of thermal annealing on ion-irradiation induced ferromagnetism of Fe-50at.%Rh bulk alloy and the related structural change were investigated by means of superconducting quantum interference device (SQUID) and extended X-ray absorption fine structure (EXAFS), respectively. Depending on the annealing temperature from 100 to 500 °C, the magnetization induced by 10 MeV iodine ion irradiation and the lattice structure of the alloy were remarkably changed. After 500 °C annealing, the magnetization and the lattice ordering of the alloy become similar to the states before the irradiation. The experimental result indicates that the thermal relaxation of irradiation-induced atomic disordering dominates the magnetic state of ion-irradiated Fe-50at.% Rh alloy.     

Physiological property and yield of the sweet sorghum mutants induced by heavy ion irradiation

Soil salinity can limit plant growth and productivity. The cultivation of tolerant varieties is convenient and cost-effective for making good use of the saline soils.The sweet sorghum plant has a high tolerance for saline alkaline soils. The KF1210-3 and KF1210-4 early-maturity mutants of sweet sorghum were obtained via carbon ion irradiation. The study assesses the productivity of three sweet sorghum cultivars(KF1210-3, KF1210-4, and KFJTCK) which were grown in intermediate(4.6 d S m~(-1)) and high(11.9 d S m~(-1)) soil salinity. The sweet sorghum grown in the soil salinity of 4.6 d S m~(-1)produced 50.00–57.30 %greater fresh weight than that in the soil salinity of11.9 d S m~(-1), while the difference was not as obvious among the dry biomass of the three sweet sorghum cultivars. Moreover, the Brix degree of the sweet sorghum grown in the soil salinity of 11.9 d S m~(-1)was greater than that grown in the soil salinity of 4.6 d S m~(-1). The heavy ion irradiation experiment is of great significance in screening plant mutants, improving environmental conditions, and assessing the productivity. This process, in turn, aids in the understanding of the effects of the biochemical and physiological mechanisms of salt stress.     

电子束辐照制备Pd/TiO2光催化薄膜

用电子束辐照浸泡在浓度分别为1×10-5、1×10-4、1×10-3、1×10-2和1×10-1mol/L的PdCl2溶液中的TiO2薄膜,在TiO2薄膜表面形成Pd纳米颗粒.通过X射线衍射(X-ray diffractometry,XRD)、场发射扫描电镜(Field emission scanning electron microscope,FESEM)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和紫外可见(Ultraviolet visible,UV-Vis)吸收光谱对辐照后的Pd/TiO2薄膜进行表征.分析表明,TiO2薄膜表面上沉积了直径20-50 nm的颗粒,为面心立方结晶的金属Pd;Pd/TiO2薄膜的UV-Vis光谱吸收边向可见光方向发生了偏移.用甲基橙作为光催化降解反应物,研究了Pd/TiO2薄膜分别在紫外光、可见光作用下的光催化降解效率.结果表明,Pd/TiO2薄膜的光催化能力显著地提高,在紫外光、可见光作用下的光催化效率分别提高了2.25倍和3.4倍.     

碳离子束辐照大豆当代诱变效应及褐皮突变体的初步研究

利用不同剂量碳离子束辐照大豆"合丰55"干种子,通过对表型、株高、分枝数及产量相关性状的考察以及DNA指纹图谱分析探索离子束辐照大豆的当代诱变效应。结果表明离子束诱变大豆M1代田间出现多种变异表型,辐照处理对M1代株高和分枝数有抑制作用,单株荚数、单株粒数、单株粒重及百粒重随着辐照剂量的增加呈现先降低后升高再降低的趋势,但这些变异与对照相比并未达到显著水平。大豆种子经辐照后M1代筛选到1株褐皮突变体,种皮颜色由黄色变为褐色,而且这种变异在M2代能够稳定遗传。运用随机扩增多态性(Random amplified polymorphic DNA,RAPD)技术对其DNA多态性进行研究发现,辐照后突变体DNA与对照相比扩增条带或增加或减少,相似性系数为0.9513。综合结果表明,碳离子束辐照对大豆当代产生了一定的诱变效应,不仅造成了农艺性状的变异,而且使DNA水平也发生了明显的变化。     

碳离子辐照诱导的甜高梁花粉生活力及花粉母细胞减数分裂的研究

为研究重离子辐照突变株的细胞遗传学变化,以碳离子辐照选育出的甜高粱早熟突变株KFJT-1及其对照品种KFJT-CK为材料,比较研究了两者之间花粉生活力大小以及花粉母细胞减数分裂的差异。结果发现：KFJT-1的花粉生活力以及花粉总数大于KFJT-CK;KFJT-1花粉母细胞减数分裂大多进入第二次减数分裂时,KFJT-CK花粉母细胞集中在第一次减数分裂;在KFJT-1减数分裂末期II,出现了两组分裂时期不一致、3分体以及不均等分裂畸变状况,畸变率仅为4．5％,说明KFJT-1在生长繁殖过程中修复了大部分由于物理诱变造成的染色体畸变,且能稳定遗传。这些结果从生殖细胞水平进一步说明碳离子辐照早熟突变株KFJT-1较未突变株KFJT-CK成熟期早,且各项指标均优于KFJT-CK。     

Modification of N-doped carbon induced by 30 MeV C60 ions

In the present work, 120 keV N-ion doped and 30 MeV C₆₀ ion irradiated graphite-like-carbon samples were characterized by RBS, micro-FTIR, micro-Raman, XPS spectroscopy and the variation of the properties of the samples with the N-dopant and/or C₆₀ irradiation fluence have been studied. The RBS spectra showed that C₆₀ irradiation can induce a partial diffusion of N atoms to the surface and the amount of the diffused N atoms increases slightly with increasing C₆₀ irradiation fluence. The FTIR and Raman spectra exhibit characteristic bands of carbon nitrogen bonds showing that the C and N atoms are chemically bonded. The amount of chemically bonded C and N atoms increases with increasing N-dopant. By deconvolution of the XPS spectra, the atomic concentration of N and C atoms were obtained and it was identified that the samples mainly consist of three phases, namely, C₃N₄, CN_x and tetrahedral amorphous carbon. The effect of N-dopant and C₆₀ irradiation fluence on the modification of the properties of the samples is also discussed.     

尼龙66/紫外辐照线性低密度聚乙烯共混物的力学性能

通过紫外辐照实现了高密度聚乙烯(HDPE)的官能化，改善了HDPE复合材料的性能。本工作采用傅立叶红外(FT-IR)、X射线光电子能谱(XPS)、凝胶、熔融指数和水接触角测试等研究了紫外辐照对线性低密度聚乙烯(LLDPE)化学结构和性能的影响。紫外辐照后，在LLDPE的分子链上引入了C=O、C-O和C(=O)O等含氧基团，其含量随辐照时间延长而增加。凝胶分析结果表明，紫外辐照过程中，LLDPE产生凝胶，     

In situ and postradiation analysis of mechanical stress in Al2O3:Cr induced by swift heavy-ion irradiation

Optical spectroscopy and TEM techniques have been applied to study the radiation damage and correlated mechanical stresses in Al₂O₃ and Al₂O₃:Cr single crystals induced by (1-3) MeV/amu Kr, Xe and Bi ion irradiation. Mechanical stresses were evaluated in situ using a piezospectroscopic effect through the shift of the respective lines in ionoluminescence spectra. It was found that dose dependence of the stress level for Xe and Bi ions, when ionization energy loss exceeds the threshold of damage formation via electronic excitations, exhibits several alternate stages showing the build-up and relaxation of stresses. The beginning of relaxation stages is observed at fluences associated with beginning of individual ion track regions overlapping. The residual stress profiles through the ion irradiated layers were deduced from depth-resolved photostimulated spectra using laser confocal scanning microscopy set-up. It was determined that stresses are compressive in basal plane and tensile in perpendicular direction in all samples irradiated with high energy ions.