GaInP/GaAs/Ge三结太阳电池不同能量质子辐照损伤模拟

以GaInP/GaAs/Ge三结太阳电池为研究对象,开展了能量为0.7, 1, 3, 5, 10 MeV的质子辐照损伤模拟研究,建立了三结太阳电池结构模型和不同能量质子辐照模型,获得了不同质子辐照条件下的I-V曲线,光谱响应曲线,结合已有实验结果验证了本文模拟结果,分析了三结太阳电池短路电流、开路电压、最大功率、光谱响应随质子能量的变化规律,利用不同辐照条件下三结太阳电池最大输出功率退化结果,拟合得到了三结太阳电池最大输出功率随位移损伤剂量的退化曲线.研究结果表明,质子辐照会在三结太阳电池中引入位移损伤缺陷,使得少数载流子扩散长度退化幅度随质子能量的减小而增大,从而导致三结太阳电池相关电学参数的退化随质子能量的减小而增大.相同辐照条件下,中电池光谱响应退化幅度远大于顶电池光谱响应退化幅度,中电池抗辐照性能较差,同时中电池长波范围内光谱响应的退化幅度比短波范围更大,表明中电池相关电学参数的退化主要来源于基区损伤.     

电子辐射环境中NPN输入双极运算放大器的辐射效应和退火特性

本文对不同偏置下的NPN输入双极运算放大器LM108分别在1.8 MeV和1 MeV两种电子能量下、不同束流电子辐照环境中的损伤特性及变化规律进行了研究, 分析了不同偏置状态下其辐照敏感参数在辐照后三种温度 (室温, 100 ℃, 125 ℃) 下随时间变化的关系, 讨论了引起电参数失效的机理, 并且分析了器件在室温和高温的退火效应以讨论引起器件电参数失效的机理. 结果表明, 1.8 MeV和1 MeV 电子对运算放大器LM108主要产生电离损伤, 相同束流下1.8 MeV电子造成的损伤比1 MeV 电子更大, 相同能量下0.32 Gy(Si)/s束流电子产生的损伤大于1.53 Gy(Si)/s束流电子. 对于相同能量和束流的电子辐照, 器件零偏时的损伤大于正偏时的损伤. 器件辐照后的退火行为都与温度有较大的依赖关系, 而这种关系与辐照感生的界面态密度增长直接相关.     

Photocarrier radiometry for noncontact evaluation of space monocrystalline silicon solar cell under low-energy electron irradiation

A space monocrystalline silicon(c-Si) solar cell under low-energy( 1 MeV) electron irradiation was investigated using noncontact photocarrier radiometry(PCR). Monte Carlo simulation(MCS) was employed to characterize the effect of different energy electron irradiation on the c-Si solar cell. The carrier transport parameters(carrier lifetime, diffusion coefficient, and surface recombination velocities) were obtained by best fitting the experimental results with a theoretical one-dimensional two-layer PCR model. The results showed that the increase of the irradiation electron energy caused a large reduction of the carrier lifetime and diffusion length. Furthermore, the rear surface recombination velocity of the Si:p base of the solar cell at the irradiation electron energy of 1 Me V was dramatically enhanced due to 1 MeV electron passing through the whole cell. Short-circuit current(I sc) degradation evaluated by PCR was in good agreement with that obtained by electrical measurement.     

1 MeV电子辐照下晶格匹配与晶格失配GaInP/GaInAs/Ge三结太阳电池辐射效应研究

对采用MOCVD方法制备的晶格匹配(LM)与晶格失配(UMM)GaInP/GaInAs/Ge三结太阳电池进行了1MeV电子辐射效应研究。结果表明:在电子辐照下,两种电池的I-V特性参数(开路电压Voc,短路电流Isc,最大输出功率Pmax)均发生衰降,且晶格失配电池的I-V特性参数衰降均大于晶格匹配电池。在光谱响应方面,对于顶电池,晶格匹配电池的衰降大于晶格失配电池;而中间电池则前者衰降小于后者;另外,Ge底电池的光谱响应表现特殊,辐照后光谱响应变强。     

远紫外光学遥感载荷在轨定标技术研究进展

远紫外波段（115～200 nm）光学遥感是在卫星上获得空间环境参数,如O,N₂和O₂等中性大气原子分子柱密度及廓线分布、电离层电子密度TEC、电子密度廓线、等离子体含量、大气温度廓线、太阳EUV流量、能量粒子沉降等信息的重要探测技术,也是最具发展潜力的空间天气探测方法之一。定量获得这些物理参量的重要过程之一是载荷的辐射定标,包括发射前实验室定标和在轨定标。发射前定标给出载荷的原始定标系数,而在轨定标则给出仪器在轨运行一段时间后定标系数的变化。远紫外探测技术用于中高层大气、电离层、磁层、太阳活动等方面的研究从19世纪70年代就已经开始,以美国为代表的一些国家已将远紫外探测列入空间天气监测的长期规划,并且开展了大量的在轨定标技术研究,确保载荷数据的长期定量化应用。我国在本世纪初才开展远紫外波段载荷技术的研究,在轨定标技术基本属于空白。在轨定标方法包括基于外部标准辐射源定标、基于内部辐射标准源定标和替代定标三种。以国际上具有代表性的远紫外探测载荷为例,分析和总结这三种定标方法分别用于成像探测、光谱成像探测和光度计三种主要的探测类型仪器上的定标方案、在轨定标数据处理方法及处理结果。对多种类型载荷及不同定标源定标方法及结果分析表明,对于视场较大,且具备深空观测能力的远紫外波段成像仪器及成像光谱仪,首选外定标源法,即采用远紫外辐射相当稳定且已知光辐射强度的的紫外恒星作为辐射标准源,根据运行轨道进行定标模式合理设计,并结合实验室定标数据,实现在轨全视场定标;对于光度计类的单点探测仪器,由于视场限制,极少有恒星观测条件,故推荐采用替代定标方式,实现载荷在轨长期监测,但在定标数据的选取及时空匹配方面应详细分析,以提高定标精度;而利用内部标准源进行定标的方法,标准源本身的衰减问题是亟待解决的问题。     

Radiation effects in silicon solar cells

Silicon solar cells have been utilized as the principal source of electrical energy for space satellites during the past decade. Despite the reliability of these photovoltaic devices, degradation of their power output by charged particle radiation in the earth's geomagnetic field has continued to be the primary problem for their use on flights of long-duration. A study of radiation damage induced by 1 MeV electrons in a variety of current silicon solar cell types has been conducted as a function of dopant impurity and resistivity of the base region. A companion study of radiation damage induced by nominal 0.2 MeV protons was performed in solar cells with coverslips having small cell areas exposed alongside the coverslip. The photovoltaic current-voltage characteristics were measured under a solar simulator emitting 140mW/cm² at air mass zero. Irradiations were performed at room temperature to fluences of 1 × 10¹⁵ e/cm² and 1 × 10¹⁵ p/cm². The efficiency of 10 ohm-cm cells after large fluences was superior to cells of 2 ohm-cm base resistivity. No significant differences were observed between boron- and aluminum-doped cells. Solar cell exposure to low energy Protons resulted in an 8 per cent loss in power at a fluence of 1 × 10¹⁴ p/cm² when as little as 2 per cent of the solar cell surface was left unshielded.     

Displacement damage analysis and modified electrical equivalent circuit for electron and photon-irradiated silicon solar cells

Solar modules and arrays are the conventional energy resources of space satellites. Outside the earth's atmosphere, solar panels experience abnormal radiation environments and because of incident particles, photovoltaic (PV) parameters degrade. This article tries to analyze the electrical performance of electron and photon-irradiated mono-crystalline silicon (mono-Si) solar cells. PV cells are irradiated by mono-energetic electrons and poly-energetic photons and immediately characterized after the irradiation. The mean degradation of the maximum power (P_max) of silicon solar cells is presented and correlated using the displacement damage dose (D_d) methodology. This method simplifies evaluation of cell performance in space radiation environments and produces a single characteristic curve for P_max degradation. Furthermore, complete analysis of the results revealed that the open-circuit voltage (V_oc) and the filling factor of mono-Si cells did not significantly change during the irradiation and were independent of the radiation type and fluence. Moreover, a new technique is developed that adapts the irradiation-induced effects in a single-cell equivalent electrical circuit and adjusts its elements. The “modified circuit” is capable of modeling the “radiation damage” in the electrical behavior of mono-Si solar cells and simplifies the designing of the compensation circuits.     

The window layers effect on the hardness improvement of space solar cells exposed to the 1 MeV electron irradiations

Because of their state of art technology, GaAs solar cells are generally preferred for spatial applications. Exposure to proton and electron irradiations, solar cells suffer significant degradation in their performance such as short circuit current and open circuit voltage. Adding a window layer helps in effectively reducing the surface recombination at the emitter surface of the solar cell without absorbing the useful light required for the device. It remains to study the physics of the window-emitter hetero-interface in order to understand how the window layer presence increases the minority carrier lifetime of the solar cell exposed to particles irradiation. In this work Numerical simulation has been used to study the AlxGa1-xAs window composition effect on the current–voltage characteristics of a GaAs solar cell under AM0 illumination and exposed to 1 MeV electron irradiation. To predict the effect of window layers on solar cells degradation, the current voltage characteristic are evaluated for different electron irradiation fluences. The findings are supported by experimental data. They lead us to get to know how the window layer improves resistance to electron irradiation through its own parameters.     

Effects of electron radiation on shielded space and triple-junction GaAs solar cells

The displacement damage dose methodology for analysing and modelling the performance of triple-junction InGaP₂/GaAs/Ge solar cells in an electron radiation environment is presented. Degradations at different electron energies are correlated with displacement damage dose (D_\rm d). One particular electron radiation environment, relative to a geosynchronous earth orbit (GEO), is chosen to calculate the total D_\rm d behind the different thicknesses coverglasses to predict the performance degradation at the end of the 15-year mission.     

Correlation between Displacement Damage Dose and Proton Irradiation Effects on GaInP/GaAs/Ge Space Solar Cells

The irradiation effects of 0.28-2.80 MeV protons on GalnP/GaAs/Ge solar cells have been analysed, and then correlated with the displacement damage dose. The results of I-V and spectral response measurements, combined with the SRIM-derived vacancies produced rates, show that the degradation of the solar cells is largely determined by the displacement damage of the GaAs sub-cell. Thus the SRIM-derived NIEL values for protons in the GaAs sub-cell are used to calculate the displacement damage dose. It is shown that the irradiation effects of the solar cells caused by protons at different energies are correlated well with the aid of displacement damage dose.     

光电耦合器电离辐射损伤电流传输比1/f噪声表征

在研究光电耦合器电离辐射损伤机理基础上,分别建立光电耦合器电离辐射损伤电流传输比(CTR)表征模型和1/f噪声表征模型.结果表明CTR退化和噪声增加都归因于辐射后光敏三极管集电结和发射结处SiO₂/Si界面缺陷增多.根据CTR退化和噪声变化分别与辐射剂量的关系,建立起噪声变化与CTR退化之间的关系,辐照实验对表征模型正确性进行了验证.运用噪声变化与辐射剂量的关系,通过低剂量辐照实验可以预测高剂量辐射后光电耦合器退化程度,故可用于评价光电耦合器抗辐射能力. 关键词： f噪声')" href="#">1/f噪声 光电耦合器 缺陷 模型     

Identification of lattice vacancies on the two sublattices of SiC

The identification of atomic defects in solids is of pivotal interest for understanding atomistic processes and solid state properties. Here we report on the exemplary identification of vacancies on each of the two sublattices of SiC by making use of (i) electron irradiation, (ii) measurements of the positron lifetimes, (iii) coincident Doppler broadening studies of the positron-electron annihilation radiation, and (iv) a comparison of the experimental data with theoretical studies. After 0.3 MeV electron irradiation, carbon vacancies V(C) are identified, where, after 0.5 MeV electron irradiation, predomi-nantly silicon vacancies V(Si) are observed. After 2.5 MeV irradiation, divacancies V(Si)-V(Si) are detected. The present results are expected to be of general importance for reliable identification of defects and atomic processes in complex solids.     

基于0级数据的星载大气痕量气体差分吸收光谱仪在轨衰变监测

大气痕量气体差分吸收光谱仪(EM I)是一种紫外可见成像光谱仪,主要用于实现高空间分辨率的全球每日大气痕量气体浓度反演.EM I在轨运行期间,受空间环境影响,元器件性能随时间推移会不断衰变.为有效监测其衰变状况,利用载荷对地各轨0级数据解析出在轨温度,实现长期在轨温度监测;通过计算各轨道星下点黑暗时的暗背景图像噪声的均...     

Verification of a generalized Planck law for luminescence radiation from silicon solar cells

A generalization of Planck's radiation law based on the principle of detailed balance predicts the emission of luminescence radiation from absorption data for direct transitions in semiconductors. Its validity for indirect transitions is questionable due to the participation of phonons. We have tested the validity for the indirect transitions in Si by measuring absolute values of the emission intensity from Si solar cells under forward bias at room temperature and find good agreement with theoretical predictions based on existing absorption data. The generalized Planck law, thus verified for the indirect transitions in Si, allows to determine the performance of solar cell materials from measuring the absolute intensity of their emission of luminescence radiation when irradiated by the sun.     

基于分布式布拉格反射器结构的空间三结砷化镓太阳能电池抗辐照研究

根据电子辐照条件下的常规三结砷化镓太阳能电池光谱响应以及电池电流的损伤特征, 确定电池衰减的物理机理: 中电池在电子辐照后形成的辐照损伤缺陷, 使得基区少子扩散长度被大幅缩短, 影响了光生载流子的收集. 针对中电池衰减的物理机理, 设计不同的基区厚度, 验证辐照后扩散长度缩短至1.5 μm左右. 为提升中电池抗辐照性能, 消除辐照后扩散长度缩减带来的影响, 对中电池外延结构进行设计, 将中电池基区减薄至1.5 μm, 并在其下方嵌入分布式布拉格反射器, 对特定波段光反射进行二次吸收, 弥补中电池减薄的影响. 通过TFCalc光学模系设计软件模拟出的中心波长为850 nm, 15对Al_0.9Ga_0.1As/Al_0.1Ga_0.9As的分布式布拉格反射器, 实际测试最高反射率大于97%, 高反带宽94 nm, 能够满足设计要求. 此基础上进行了新结构电池的外延生长与辐照测试对比. 实验结果表明: 新结构太阳能电池辐照后短路电流衰减比原结构降低了50%, 效率的剩余因子提升2.3%.     

Light‐induced degradation and regeneration of multicrystalline silicon Al‐BSF and PERC solar cells

Light‐induced degradation (LID) is a well‐known problem faced by p‐type Czochralski (Cz) monocrystalline silicon (mono‐Si) wafer solar cells. In mono‐Si material, the physical mechanism has been traced to the formation of recombination active boron‐oxygen (B–O) complexes, which can be permanently deactivated through a regeneration process. In recent years, LID has also been identified to be a significant problem for multicrystalline silicon (multi‐Si) wafer solar cells, but the exact physical mechanism is still unknown. In this work, we study the effect of LID in two different solar cell structures, aluminium back‐surface‐field (Al‐BSF) and aluminium local back‐surface‐field (Al‐LBSF or PERC (passivated emitter and rear cell)) multi‐Si solar cells. The large‐area (156 mm × 156 mm) multi‐Si solar cells are light soaked under constant 1‐sun illumination at elevated temperatures of 90 °C. Our study shows that, in general, PERC multi‐Si solar cells degrade faster and to a greater extent than Al‐BSF multi‐Si solar cells. The total degradation and regeneration can occur within ～320 hours for PERC cells and within ～200 hours for Al‐BSF cells, which is much faster than the timescales previously reported for PERC cells. An important finding of this work is that Al‐BSF solar cells can also achieve almost complete regeneration, which has not been reported before. The maximum degradation in Al‐BSF cells is shown to reduce from 2% (relative) to an average of 1.5% (relative) with heavier phosphorus diffusion.     

电子辐照下GaAs/Ge太阳电池载流子输运机理研究

通过地面模拟辐照试验获得不同能量电子辐照下GaAs/Ge太阳电池电学参数退化的基本规律, 在此基础上使用PC1 D模拟程序分析太阳电池内部的载流子输运机理, 建立不同能量的电子辐照下GaAs/Ge太阳电池中多数载流子浓度和少数载流子扩散长度随辐照粒子注量变化的基本规律. 研究结果表明: 多数载流子浓度和少数载流子扩散长度均随入射电子注量的增大而减小, 多数载流子去除率和少数载流子扩散长度损伤系数均随电子能量的增高而增大, 多数载流子去除效应和少数载流子扩散长度缩短分别是电池开路电压和短路电流退化的主要原因.     

Effect of 10 MeV electron irradiation on dye-sensitized solar cells

The effect of 10?MeV electrons’ irradiation on dye-sensitized solar cells (DSSCs) has been studied in this paper. J–V characteristics measurements were carried out in order to investigate the degradation of the cells in electron radiation environments. The short-circuit current (J_sc) and maximum power density (P_max) of cells decrease significantly after the electron irradiation. When the irradiation dose increases to 10?kGy, the initial maximum power decreases nearly by 50%. The influences of the electron irradiation on FTO, dye sensitizer and anode were studied to investigate the degradation mechanism of DSSC, respectively. The ultraviolet–visible spectra of FTO show that the absorption peaks of dye decrease, resulting in a decline of the FTO transmittance. According to the X-ray diffraction measurement results, it was found that the particle size of nano-crystalline TiO₂ had changed after the electron irradiation. With the help of SEM, the conglomeration of TiO₂ nano-particles appears after the electron irradiation.     

A new approach to determine accurately minority-carrier lifetime

Electron or proton irradiations introduce recombination centers, which tend to affect solar cell parameters by reducing the minority-carrier lifetime (MCLT). Because this MCLT plays a fundamental role in the performance degradation of solar cells, in this work we present a new approach that allows us to get accurate values of MCLT. The relationship between MCLT in p-region and n-region both before and after irradiation has been determined by the new method. The validity and accuracy of this approach are justified by the fact that the degradation parameters that fit the experimental data are the same for both short-circuit current and the open-circuit voltages. This method is applied to the p⁺/n-InGaP solar cell under 1 MeV electron irradiation.