【作者】 胡建民；

【导师】 杨德庄； 吴宜勇；

【作者基本信息】 哈尔滨工业大学 ， 材料学， 2009， 博士

【摘要】 本文通过空间带电粒子辐照地面等效模拟试验,研究了国产GaAs/Ge单结太阳电池和GaInP/GaAs/Ge三结太阳电池的电学性能演化规律和辐照损伤机理。在此基础上,对GaAs/Ge单结太阳电池的在轨性能退化预测方法进行了简化和改进,并将其推广应用于GaInP/GaAs/Ge三结太阳电池。针对地球同步轨道环境条件,预测了国产GaAs/Ge单结太阳电池和GaInP/GaAs/Ge三结太阳电池的在轨服役行为。研究结果表明,不同能量质子辐照下,GaAs/Ge单结太阳电池的电学性能退化与电池发射区、基区和空间电荷区不同程度的损伤密切相关。70keV质子主要造成电池空间电荷区损伤,导致电池开路电压明显退化,40keV质子主要造成电池发射区损伤,导致电池短路电流显著降低。大于100keV质子辐照下,电池短路电流、开路电压和最大功率的退化幅度均随质子能量提高逐渐降低。电子辐照注量一定时,GaAs/Ge电池电学性能的退化幅度随电子能量增加而增大。1MeV电子和170keV质子的辐照次序对电池的辐照损伤效应没有影响。DLTS分析表明,<200keV质子辐照在GaAs/Ge电池中引入的辐照缺陷主要有Ec-0.31eV和Ec-0.47eV,且随质子能量的增加,缺陷浓度逐渐降低。在辐照损伤效应研究的基础上,针对GaAs/Ge太阳电池,建立了短路电流和开路电压退化的数学/物理模型。<200keV质子辐照下,GaInP/GaAs/Ge三结电池的电学性能退化与质子能量密切相关。在一定的辐照注量下,170keV质子辐照造成电池开路电压、短路电流和最大功率的退化幅度最大;与之相比,40、100和130keV质子辐照引起电池电学性能退化幅度相对较小。4MeV和10MeV质子辐照下,电池的电学性能退化幅度随质子能量的增加逐渐减小。在一定的电子注量下,电池电学性能的退化幅度随电子能量提高而增大。采用光学深能级瞬态谱法分析了三结GaInP/GaAs/Ge太阳电池的深能级缺陷。研究结果表明,<200keV质子辐照在GaInP子电池中引入的深能级缺陷主要有Ec-0.26eV、Ev+0.18eV和Ev+0.42eV;在GaAs子电池中产生的深能级缺陷主要有Ec-0.015eV、Ec-0.15eV和Ev+0.33eV。从试验和理论分析两方面,研究了<200keV质子通量对GaAs/Ge太阳电池辐照损伤效应的影响。结果表明,质子通量在6×109~1.2×1011cm-2s-1范围内,对GaAs/Ge太阳电池的辐照损伤效应没有影响,为进行空间带电粒子辐照地面等效模拟加速试验提供了依据。针对国产GaAs/Ge和GaInP/GaAs/Ge太阳电池,建立了不同能量电子和质子辐照下太阳电池电学性能退化曲线与动力学方程。在此基础上,确定了国产太阳电池不同能量粒子注量转换的相对损伤系数。通过Monte-Carlo方法计算了透过太阳电池防护盖片的空间带电粒子能谱及轨道等效注量,简化了等效注量法的计算过程。在低能质子辐照损伤效应研究的基础上,针对国产GaAs/Ge单结太阳电池,确定了<70keV质子和>70keV质子辐照位移损伤剂量转化的相对等效系数,对NRL的位移损伤剂量法进行了改进。将改进的位移损伤剂量法推广应用于GaInP/GaAs/Ge三结太阳电池。采用改进的等效注量法和位移损伤剂量法,预测了表面加装120μm防护盖片的国产GaAs/Ge太阳电池和GaInP/GaAs/Ge太阳电池在地球同步轨道的电学性能退化。两种评价方法的预测结果一致,说明改进后的评价方法具有实际应用的可行性。更多还原

【Abstract】 The degradation and damage mechanisms caused by irradiation of space charged particles are investigated for the domestic GaAs/Ge and GaInP/GaAs/Ge solar cells, based on equivalent ground simulation experiments. The methods of evaluating performance in orbit for the GaAs/Ge single-junction solar cells are simplified and improved, and are further applied to the GaInP/GaAs/Ge triple-junction solar cells. The performance of the GaAs/Ge and GaInP/GaAs/Ge solar cells in the geostationary orbit is evaluated.Experimental results show that under exposure of protons with various energies, the degradation in electric characteristics of the GaAs/Ge single-junction solar cells can be related to the damage in the emitter, the base and the space charge regions, respectively. The 70keV protons primarily lead to the damage in the space charge region and an obvious degradation in the open voltage. The 40keV protons mainly result in the damage in the emitter and a considerable degradation in short circuit current. Under the >100keV protons exposure, the degradation of electric properties gradually decrease with increasing proton energy. Compared at a given fluence of electrons, the electric characteristics of the GaAs/Ge solar cells increase with increasing electron energy. The exposure sequence of 1MeV electrons and 170keV protons does not influence irradiation damage to the GaAs/Ge cells. DLTS analysis shows that the irradiation-induced defects caused by <200keV protons in the GaAs/Ge solar cells are mainly the Ec-0.31eV and Ec-0.47eV, and their concentration decreases with increasing proton energy. On the basis of the irradiation-induced damage effects, two physical-mathematic models on the degradation in electric characteristics of the GaAs/Ge single-junction cells are set up, which are separately responsible for the short circuit current and the open circuit voltage.Under <200keV proton exposure, the degradation in electric characteristics of the GaInP/GaAs/Ge triple-junction cells has a close relationship with proton energy. Compared at a given fluence, the 170keV proton exposure leads to the largest degradation magnitude of the open circuit voltage, short circuit current and maximum power. In contrast, the degradation magnitude in the electric characteristics caused by the 40, 100 and 130keV protons is lower. Under the irradiation of protons with 4MeV and 10MeV, the degradation magnitude in electric characteristics decreases with increasing proton energy. At a given fluence, the degradation magnitude in electric characteristics increases with increasing electron energy. ODLTS analysis shows that the <200keV protons can introduce the deep-energy levels of Ec-0.26, Ev+0.18eV and Ev+0.42eV in the GaInP sub-cell, and those of Ec-0.015eV, Ec-0.15eV and Ev+0.33eV in the GaAs sub-cell.The effect of <200keV proton flux on the radiation damage of the GaAs/Ge single-junction cells is studied, on both the experimental and theoretical analyses. It is shown that the proton flux ranged from 6×109 to 1.2×1011cm-2s-1 does not have effects on the radiation damage of the GaAs/Ge cells. This can provide a basis of accelerating ground simulation for space charged particle irradiation. Both degradation curves and the dynamic equation for the electric characteristics of the domestic GaInP/GaAs/Ge cells are established through experiments. Also, the relative damage coefficients to convert fluences for particles with different energies are given for the domestic GaAs/Ge and GaInP/GaAs/Ge cells. The equivalent fluences for orbits are calculated in terms of the energy spectra of space charged particles that penetrate through the coverglass. As a result, the calculation for the equivalent fluence method can be simplified.On the basis of radiation-induced damage effects caused by protons with lower energies, the relative equivalent coefficients to convert the displacement damage doses for the <70keV protons and >70keV protons are given for the domestic GaAs/Ge cells. Furthermore, the improved displacement damage dose method is applied to evaluating the GaInP/GaAs/Ge triple-junction cells. The degradation behaviors in the geostationary orbit of the domestic GaAs/Ge and GaInP/GaAs/Ge cells with a coverglass plate of 120μm in thickness are predicted, using both the improved equivalent fluence method and displacement damage dose method. The predicting results are in good agreement for the two evaluating methods, illustrating that the improved predicting methods are applicable in practice.更多还原