GaAs太阳电池1MeV电子辐射效应数值模拟

简要介绍了太阳电池的基本工作原理和辐射损伤机理。利用二维半导体器件数值模拟软件MEDICI,模拟计算了1MeV高能电子在辐射通量范围为1×1013～1×1015cm2时,对GaAs太阳电池主要输出参数(如开路电压Voc,短路电流Isc)的影响,并对计算结果进行了分析,计算结果与相关文献给出的实验数据吻合较好。     

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.     

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.     

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.     

碳离子辐射对空间GaAs/Ge太阳电池性能影响的研究

利用2×1.7 MV串列静电加速器提供的碳(C)离子束模拟空间环境辐射,对空间GaAs/Ge太阳电池用注量为3.1×109-6.9×1012 cm-2的2 MeV C离子进行辐照.通过Ⅰ-Ⅴ特性和光谱响应测试,研究分析了GaAs/Ge太阳电池的C离子辐射效应.结果表明:随着C离子辐照注量的增加,GaAs/Ge太阳电池电性能参数Isc、Voc和Pmax衰降增大,其中Pmax衰降最大,Isc次之,Voc最小.该衰降规律和质子辐照的衰降规律相似.但使GaAs/Ge太阳电池的Pmax衰降到原值的50%,用C离子辐照所需注量要比相同射程的质子辐照小两个量级.在低注量辐照时,光谱响应衰降主要发生在长波范围;而注量大于3.1×1010 cm-2时,则发生明显的长、短波整个波段的光谱响应衰降;当注量增大到2.3×1011 cm-2以上,光谱响应基本消失.     

GaAs太阳电池引入量子阱结构后抗辐射性能的变化

利用2×1.7 MV串列静电加速器提供的质子束模拟空间环境辐射,对引入量子阱GaAs太阳电池和无量子阱GaAs太阳电池进行2MeV质子注量为1×109-2×1013cm-2的辐照,通过电池Ⅰ-Ⅴ特性和光谱响应测试,研究分析了它们的辐射效应.结果表明这两种电池的Isc、Voc和Pmax的衰降幅度均随辐照注量增加而增大;而相同注量的辐照,引入量子阱GaAs太阳电池电性能衰降幅度要比无量子阱GaAs太阳电池的大.经2×1013cm-2质子辐照后,引入量子阱GaAs太阳电池光谱响应在400-1000nm整个波段有明显衰降,且长波区(900-1000 nm)的量子阱特性消失.量子阱结构的引入使GaAs太阳电池的抗辐射性能下降.     

空间实用GaAs/Ge太阳电池高能质子辐射效应研究

用能量为5—20MeV,注量为1×109—7×1013 cm-2的高能质子对空间实用GaAs/Ge太阳电池进行辐照,得到了其性能随质子能量和注量的变化关系,并进行了微观机理的讨论。研究结果表明,注量低于1×109 cm-2的质子辐照不会引起太阳电池性能的变化; 注量高于1×109 cm-2辐照,会引起太阳电池性能的改变。当注量为3×1012 cm-2时,5、10、20 MeV质子辐照引起太阳电池性能参数Isc衰降变化分别是原值的80%、86%、90%;Voc衰降变化分别为原值的82%、85%、88%;Pmax衰降的变化分别为原值的60%、64%、67%。当辐照注量为5×1013 cm-2时,5、10、20 MeV质子辐照引起Pmax衰降的变化分别为原值的26%、30%、36%。即随着注量的增加,太阳电池性能衰降增大;且相同注量的辐照,质子能量愈高,太阳电池性能衰降愈小。这与质子在电池材料中的能量损失和辐照引入的深能级Ec-0.41eV有关。     

一种国产GaInP/GaAs/Ge三结太阳电池的电子辐照特性

对一种国产GaInP/GaAs/Ge三结太阳电池进行了1 MeV电子辐照损伤研究,分析和讨论了不同注量电池电参数和光谱响应的衰降规律.实验结果表明,这种电池不但有很高的初始效率,而且有好的抗辐射性,电子注量达到1×1015 cm-2时,最大输出功率为辐照前的80.4%.辐照后GaInP顶电池几乎不发生退化,而GaAs中间电池短路电流严重退化,致使GaInP顶电池与GaAs中间电池电流失配,是GaInP/GaAs/Ge电池性能退化的主要原因.     

电子辐照GaInP/GaAs/Ge三结太阳电池少子寿命的变化

为研究电子辐照空间太阳电池的损伤机制,对电子辐照GaInP/GaAs/Ge三结太阳电池进行了光致发光谱测量,分析了GaInP顶电池及GaAs中间电池发光强度随电子注量的变化规律。利用辐射效率关系对归一化发光强度随电子辐照注量的变化进行了拟合,分别得到了GaInP顶电池及GaAs中间电池在不同辐照条件下的少子非辐射复合寿命τ_nr,通过对比辐照前后少子非辐射复合寿命的衰降变化,发现GaInP顶电池的抗辐照性能优于GaAs中间电池。     

A study on the degradation of GaAs/Ge solar cells irradiated by <200 keV protons

Damage effects in GaAs/Ge solar cells irradiated by <200 keV protons were studied by measuring their electrical properties and spectral response together with SRIM simulations. Proton energies of 40, 70 and 170 keV were chosen. Experimental results show that the short circuit current, open circuit voltage and maximum power decrease with increasing proton fluence. The degradation of the open circuit voltage is highest for 70 keV irradiation and lowest for 40 keV irradiation. The degradation of short circuit current decreases with increasing proton energy. According to SRIM simulations and spectral response analysis, the above changes in electrical properties are mainly related to damage in different regions of the solar cells.     

A characterisation of electronic properties of alkaline texturized polycrystalline silicon solar cells using IBIC

In this study, electronic properties of p-type alkaline texturized polycrystalline silicon solar cells were investigated using ion beam induced charge (IBIC) analysis. With this technique, quantitative information on electronic diffusion lengths and average electronic capture cross sections of lattice defects generated by high energy protons were obtained. Angular-resolved IBIC analysis was used to quantify the electronic diffusion lengths. For this purpose, the experimental data were fitted using a simulation based on the Ramo-Shockley-Gunn (RSG) theorem and the assumption of an abrupt pn-junction. In order to determine the average electronic capture cross section of proton-induced lattice defects, the loss of charge collection efficiency (CCE) was plotted vs. the accumulated ion fluence. As will be demonstrated, a simple model based on charge carrier diffusion and Shockley-Read-Hall (SRH) recombination is able to fit the CCE loss well. Furthermore, spatially and energetically highly resolved IBIC-maps of grain boundaries were recorded. A comparison with PIXE-maps shows that there is no correlation observable between CCE variations at grain boundaries and metallic impurities within the PIXE detection limits of a few ppm. On the contrary, there is an evident correlation to the morphology of the sample’s surface as was observed by comparing IBIC-maps and SEM-micrographs. These local CCE fluctuations are dominated by the interplay of charge carrier diffusion processes and the sample surface morphology.     

直拉单晶硅太阳能电池光致衰减效应的正电子湮没谱研究

采用正电子湮没辐射多普勒展宽谱研究了光照和热处理对直拉单晶硅太阳能电池微观缺陷和输出特性的影响。结果表明:随着光照时间的增加,太阳能电池的转换效率逐渐下降,照射超过12h后达到一个稳定值;将辐照后样品在200℃下热处理2h后,转换效率逐渐回复;电池中的硼氧复合体缺陷的激活和钝化导致电池转换效率和多普勒展宽谱的变化。     

A study on the effects of the proton flux on the irradiated degradation of GaAs/Ge solar cells

Low-energy proton irradiation is one of the important factors which affect applications of GaAs solar cells in space. The proton flux encountered in orbit is much lower than that used during ground-base radiation experiments, thus ground-based experiments are a so-called accelerated simulating process. In this paper, effects of the proton flux on the degradation of GaAs/Ge solar cells using I-V measurements are investigated. The results indicate that low-energy irradiation seriously damages the solar cells. Regardless of the proton energy, the radiation flux shows no influence on the degradation process of the solar cell. The mechanisms for these effects are discussed in detail here.     

辐射和热同时作用对膨润土物理化学性质和微观结构影响的初步研究北大核心CSCD

为了研究γ辐射和热同时作用对膨润土的影响,以高庙子改性钠基膨润土为研究对象,开展了90℃热作用下、不同剂量率和不同累积剂量的γ辐射老化试验。结果表明:γ辐射和90℃热同时作用引起了膨润土物理化学性质和微观结构的变化。在老化作用后,膨润土的吸水率、pH值、阳离子交换容量、层荷以及蒙脱石001晶面方向的微晶尺寸均减小,比参考样分别降低了(最大减幅)18.4%、7.8%、3.4%、2.9%和15.6%,且表现出剂量率效应;老化作用对膨润土的矿物成分及含量影响较小。在高放废物地质处置的工程屏障设计和安全评价中,应考虑膨润土性质变化的影响因素。     

Adsorption and thermal stability of alkanethiol films on GaAs(110): A comparative study by TOF-DRS and TOF-SIMS

We present an ion beam study of the adsorption and the thermal stability of short alkanethiol molecules adsorbed on GaAs(110). Direct recoiling spectroscopy shows that the adsorption of ethanethiol and hexanethiol proceeds directly towards a dense standing up phase without passing through a stable phase of lying down molecules as is the case for Au(111). Measurements along specific azimuths suggest that both Ga and As rows are covered by the organic molecules. Short adsorption times from the vapor phase result in films having two desorption peaks near 300 and 500 K. On the other hand, leaving the sample in a thiol atmosphere for several hours produces more stable films, similar to those produced by immersion in the corresponding thiol-ethanol solution. TOF-SIMS results confirm the C-S scission mechanism during the thermal desorption.     

重离子辐射致肝癌细胞DNA损伤的时间效应初探

以SMMC-7721肝癌细胞为材料，采用单细胞凝胶电泳(Single cell gel electrophoresis，SCGE)实验方法，利用兰州近代物理研究所重离子研究装置(HIRFL)产生的氖离子(80MeV/u^20Ne^10 )，研究重离子对肿瘤细胞DNA的损伤程度随时间的变化情况。结果表明，重离子辐照所致原初损伤与剂量呈线性正相关；继续培养24h内有明显的DNA两次损伤现象。     

Influence of various catalysts on the radiation resistance and the mechanical properties of cyanate ester/epoxy insulation systems

Fiber reinforced composites impregnated with mixtures of various cyanate ester and epoxy resins demonstrated their excellent performance at the ITER design fluence and beyond. The insulation systems consist of a wrapped R-glass/Kapton reinforcement, vacuum impregnated with a cyanate ester/epoxy blend. For the fabrication of the insulation a long pot-life of the resin is of great importance, which is mainly determined by the amount and the composition of the catalyst needed for curing the resin. However, the catalyst, which amounts to 1–2% of the resin, may also affect the mechanical properties as well as the radiation hardness of the material. In order to investigate these effects, two different composites were fabricated using a Mn- and a Co-catalyst, respectively.The mechanical properties are characterized prior to and after irradiation to a fast neutron fluence of 1 × 10²² m⁻² (E > 0.1 MeV) in tension and interlaminar shear at 77 K.     

高温及γ辐照老化对改性钠基膨润土影响的初步研究

为了确认高温及γ辐照对改性钠基膨润土的影响.以内蒙古高庙子改性钠基膨润土为研究对象,利用X射线衍射仪和同步热分析仪分析了高温热老化、γ辐照老化和γ辐照-热程序老化作用对改性钠基膨润土性能和微观结构的影响.发现单纯热作用或单纯的辐照作用影响较小,而辐射-热程序老化作用会显著影响改性钠基膨润土的微观结构.经过1000 kG...     

Investigations on the structural and optical properties of the swift heavy ion irradiated 6HSiC

Single crystal 6HSiC wafers have been irradiated with 150 MeV Ag¹²⁺ ions with fluences ranging from 1 × 10¹¹ to 1 × 10¹³ ions/cm² at 300 K. The defect accumulation as a function of fluence was studied to determine changes in structural and optical properties. The variation in the fundamental Raman modes of the crystalline 6HSiC due to irradiation has been correlated with the disorder accumulation. The creation of defect states due to irradiation in the bandgap affects the blue-green photoluminescence emission in the irradiated samples. The UV-Visible absorption studies support the existence of defect states in the bandgap which is observed by the shift in the absorption edge towards the lower energy side with increasing fluence. Time Correlated Single Photon Counting photoluminescence decay results suggest that the existing defect states are radiative, exhibiting three lifetimes when irradiated with a fluence 5 × 10¹¹ ions/cm². The total number of lifetime components was reduced for a fluence 1 × 10¹³ ions/cm² as the defect states produced increase the non-radiative defect centres. These results suggest that the accumulation of defects due to irradiation at fluences 5 × 10¹¹ and 1 × 10¹³ ions/cm² are degenerate configurations which exhibit multiple lifetimes in photoluminescence studies. It is inferred that the optically active defect states influence the transition rate of charge carriers in this device material.     

荷能团簇束成膜的表面迁移和附着特性的研究

研究了不同能量的团簇碰撞有机物（CH3SiO3/2)衬底形成的表面形貌。结果表明,团簇能量的增大、增加了团簇原子在基片表面的有效碰撞能和迁移力,也改善了沉积薄膜的附着性、致密性、平整性等。特别是有机物上修饰条纹的出现,是迁移力增加的有力证据。