多结太阳电池辐射损伤的电致发光研究

建立了电致发光测试方法,对一种国产GaInP/GaAs/Ge三结太阳电池1MeV电子辐照后各子电池的辐照特性进行了研究,并与光谱响应结果进行了比较。讨论了GaInP/GaAs/Ge三结太阳电池的辐射损伤机理。     

国产高效GaInP/GaAs/Ge三结太阳电池的低能质子辐射效应

运用2×1.7MV串列静电加速器提供的质子束,对MOCVD方法制备的GaInP/GaAs/Ge三结电池进行低能质子辐射效应研究.选质子能量为0.28,0.62和2.80MeV,辐照注量为1×1010,1×1011,1×1012和1×1013cm-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.研究结果表明:随辐照注量的增加,太阳电池性能参数Lsc,Voc和Pmax的衰降幅度均增大;但随质子辐照能量的增加,Lsc,Voc和Pmax的衰降幅度均减小.实验中0.28MeV质子辐照引起电池Lsc,Voc,Pmax衰降最显著,三结电池中光谱响应衰降最明显的是中间GaAs电池.     

国产高效GaInP/GaAs/Ge三结太阳电池的低能质子辐射效应

运用2×1.7MV串列静电加速器提供的质子束,对MOCVD方法制备的GaInP/GaAs/Ge三结电池进行低能质子辐射效应研究.选质子能量为0.28,0.62和2.80MeV,辐照注量为1×1010,1×1011,1×1012和1×1013cm-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.研究结果表明:随辐照注量的增加,太阳电池性能参数Lsc,Voc和Pmax的衰降幅度均增大;但随质子辐照能量的增加,Lsc,Voc和Pmax的衰降幅度均减小.实验中0.28MeV质子辐照引起电池Lsc,Voc,Pmax衰降最显著,三结电池中光谱响应衰降最明显的是中间GaAs电池.     

基于金属背支撑刻蚀技术的柔性AlGaInP/AlGaAs/GaAs三结太阳电池研制

对柔性GaAs基太阳电池的制备方法进行研究,报道了一种用于制备柔性倒置生长的AlGaInP/AlGaAs/GaAs三结太阳电池的剥离和转移方法——金属背支撑选择性湿法刻蚀技术.在GaAs/GaInP选择性腐蚀的基础上进行了GaAs衬底层的腐蚀,研究了不同类型和体积比的溶液对GaAs/GaInP/AlInP结构腐蚀的选择特性,最终选用不同配比的H2 SO4-H2 O2系腐蚀液,获得快速、可控制、重复性好的去除衬底的两步腐蚀法.原子力显微镜测试结果表明,通过此方法能够成功地将电池外延层薄膜转移到Cu衬底上,并且在剥离和转移过程中外延层薄膜没有受到损伤.柔性AlGaInP/AlGaAs/GaAs三结太阳电池的开路电压超过3.4V.     

空间实用背场Si太阳电池和GaAs/Ge太阳电池性能随质子辐照注量变化的比较

研究了空间实用背场Si太阳电池和GaAs/Ge太阳电池性能随质子辐照注量1×109～5×1013cm-2的变化.实验表明,两种太阳电池的电性能随辐照注量增加有不同的衰降趋势.背场Si太阳电池性能参数Isc、Voc和Pmax衰降变化快,辐照注量为2×1010cm-2时,Pmax就已衰降为原值的75%;而GaAs/Ge电池对应相同的衰降辐照注量达8×1011cm-2,且其Isc、Voc和Pmax衰降变化起初缓慢,当辐照注量接近3×1012cm-2时才迅速下降.背场Si电池和GaAs/Ge电池性能衰降分别与质子辐照引入的Ev+0.14eV及Ev+0.43eV和Ec-0.41eV深能级有关.     

空间实用背场Si太阳电池和GaAs/Ge太阳电池性能随质子辐照注量变化的比较

研究了空间实用背场Si太阳电池和GaAs/Ge太阳电池性能随质子辐照注量1×109～5×1013cm-2的变化.实验表明,两种太阳电池的电性能随辐照注量增加有不同的衰降趋势.背场Si太阳电池性能参数Isc、Voc和Pmax衰降变化快,辐照注量为2×1010cm-2时,Pmax就已衰降为原值的75%;而GaAs/Ge电池对应相同的衰降辐照注量达8×1011cm-2,且其Isc、Voc和Pmax衰降变化起初缓慢,当辐照注量接近3×1012cm-2时才迅速下降.背场Si电池和GaAs/Ge电池性能衰降分别与质子辐照引入的Ev+0.14eV及Ev+0.43eV和Ec-0.41eV深能级有关.     

连续激光对三结GaAs电池的损伤效应北大核心CSCD

在空气中和真空中,利用波长为1070nm的连续(CW)激光辐照三结砷化镓(GaAs)太阳电池,通过测试激光辐照前后电池的电流-电压曲线,并利用激光诱导电流(LBIC)成像系统和X射线光电子能谱仪(XPS),研究了三结GaAs太阳电池的损伤情况。结果表明,当激光功率密度为8.4 W/cm2、辐照时间为10s时,在空气中,底电池Ge熔融短路;在真空中,顶电池Ga0.5In0.5P和底电池Ge均发生短路,说明三结GaAs太阳电池的底电池最容易受到破坏,且电池在真空中比在空气中更容易受到损伤。该研究结果可为三结GaAs太阳电池的激光无线能量传输和损伤机理的研究提供一定的参考。     

半导体激光器辐照损伤效应实验研究进展

半导体激光器(LD)工作在空间辐射或核辐射环境中时,会受到辐照损伤的影响而导致器件性能退化。文章回顾了不同时期研制的LD(从早期的GaAs LD到量子阱LD和量子点LD)在辐照效应实验方面的研究进展,梳理了国际上开展不同辐射粒子或射线(质子、中子、电子、伽马射线)诱发LD辐射敏感参数退化的实验规律,分析总结了当前LD辐照效应实验方法研究中亟待解决的关键技术问题,为今后深入开展LD的辐照效应实验方法、退化规律、损伤机理及抗辐射加固技术研究提供理论指导和实验技术支持。     

高倍聚光GaInP/InGaAs/Ge三结太阳电池研究

在综述高倍聚光GaInP/InGaAs/Ge三结太阳电池的研究现状与发展趋势的基础上,对高倍聚光太阳电池的关键技术、性能提升方法和可靠性进行了研究。指出提高隧穿电流和降低串联电阻是高倍聚光三结太阳电池的关键技术,并提出了相应的解决方法。采用多异质结构隧穿结提高了隧穿电流,减小横向扩展电阻和栅线电阻降低了总的串联损耗。此外,通过分别提高GaInP顶电池和底电池禁带宽度、降低InGaAs中电池禁带宽度可进一步提高太阳电池的转换效率。最后探讨了高倍聚光太阳电池的可靠性测试标准。     

GaAs/Ge太阳电池异常I-V特性曲线分析

分析了GaAs/Ge单结太阳电池研制中两种异常I-V特性曲线出现的主要原因:GaAs/Ge界面的相互扩散,形成附加结或附加势垒;并获得与实验有很好吻合的计算模拟结果,进一步证实了理论分析.此外,在上述分析的指导下,通过降低生长温度和优化成核条件,成功获得了效率为20.95%(AM0,25℃,2cm× 4cm)的GaAs/Ge太阳电池.     

Theoretical analysis on GaAs sub-cell doping concentration for triple-junction solar cells irradiated by proton based on TCAD simulation

The degradation on the GaInP/GaAs/Ge triple-junction solar cells was irradiated by proton, and the solar cells with various GaAs sub-cell doping concentrations are modeled by the technology computer aided design (TCAD) simulation. The degradation results of related electrical parameters and external quantum efficiency (EQE) are studied. The degradation mechanism irradiated by proton is discussed. The short-circuit current, maximum power and conversion efficiency decrease with the increasing of GaAs sub-cell doping concentration. When the base doping concentration of GaAs sub-cell is 1×1016 cm-3, the degradation of short-circuit current is less than that of other base doping concentrations. Furthermore, under proton irradiation, with the increase of doping concentration of GaAs sub-cell, the open-circuit voltage first increases and then decreases. Meanwhile, when the base doping concentration of GaAs sub-cell is 2×1017 cm-3, the degradation of open-circuit voltage is less than that of other base doping concentrations. The research will provide the basic theories and device simulation method for GaInP/GaAs/Ge triple-junction solar cells radiation damage evaluation study and radiation hardening, and can provide guidance for the production of triple-junction solar cells in orbit.     

Analytical model for multi-junction solar cells prediction in space environment

Multi-junction solar cells, as other semiconductor devices, suffer degradation of their electrical and physical properties under particle irradiation (electrons and protons) in space environment. In this paper we present an analytical model in order to make predictions of multi-junction solar cells (GaInP/GaAs/Ge) degradation in space environment.     

Designing of 1 eV GaNAs/GaInAs superlattice subcell in current-matched four-junction solar cell

A reasonably-thick GaNAs/GaInAs superlattice could be an option as a roughly 1 eV subcell to achieve high-efficiency multi-junction solar cells on a lattice-matched Ge substrate. A detailed consideration of a high-efficiency design for a GaInP/GaAs/1 eV/Ge device is presented. Calculations have been done for this structure to obtain the confined energies of the electrons and holes by utilizing the Kronig-Penney model, as well as the absorption coefficient and thereby the external quantum efficiency. The effect of well layers, GaNAs or GaInAs, on the absorption and photocurrent density under the AM 1.5 condition is discussed in order to realize a requirement of current matching in the four-junction solar cells. The management of these considerations implies the feasibility of the GaNAs/GaInAs superlattice subcell design to improve the overall conversion efficiency of lattice matched GaInP/GaAs/1 eV/Ge cells.     

Evaluating electron induced degradation of triple-junction solar cell by numerical simulation

In this paper, the degradation related parameters of GaInP/GaAs/Ge triple-junction solar cell induced by electron irradiation are carried out by numerical simulation. The degradation results of short-circuit current, open-circuit voltage, maximum power have been investigated, and the degradation mechanism is analyzed. Combining the degradation results, the degradation of normalized parameters versus displacement damage dose is obtained. The results show that the degradation increases with the increase of the electron fluence and electron irradiation energy. The degradation normalized related parameters versus displacement damage dose can be characterized by a special curve that is not affected by the type of irradiated particles. By calculating the annual displacement damage dose and the on-orbit operation time of special space orbit, the degradation of normalized parameters can be obtained with the fitting curve in the simulation. The study will provide an approach to estimate the radiation damage of triple-junction solar cell induced by space particle irradiation.     

Breakeven criteria for the GaInNAs junction in GaInP/GaAs/GaInNAs/Ge four‐junction solar cells

The four‐junction GaInP/GaAs/GaInNAs/Ge solar cell structure holds the promise of efficiencies exceeding those of the GaInP/GaAs/Ge three‐junction cell, which at present is the benchmark for high‐efficiency multijunction cell performance. The performance of GaInNAs junctions demonstrated to date has been insufficient for the realization of these projected efficiency gains, owing to poor minority‐carrier properties in the GaInNAs. However, incremental improvements in the GaInNAs junctions have brought this breakeven point within sight. In this paper, we use a semiempirical approach to estimate the efficiency of the GaInP/GaAs/GaInNAs/Ge four‐junction solar cell structure as a function of the performance parameters of the GaInNAs third junction. The results provide guidance on the extent to which the current and voltage of present‐day GaInNAs junctions will need to be improved in order for the resulting four‐junction cell to realize its potential for efficiencies higher than that of GaInP/GaAs/Ge benchmark. Published in 2002 by John Wiley & Sons, Ltd.     

Germanium subcells for multijunction GaInP/GaInAs/Ge solar cells

Photovoltaic converters based on n-GaInP/n-p-Ge heterostructures grown by the OMVPE under different conditions of formation of the p-n junction are studied. The heterostructures are intended for use as narrow-gap subcells of the GaInP/GaInAs/Ge three-junction solar cells. It is shown that, in Ge p-tn junctions, along with the diffusion mechanism, the tunneling mechanism of the current flow exists; therefore, the two-diode electrical equivalent circuit of the Ge p-n junction is used. The diode parameters are determined for both mechanisms from the analysis of both dark and “light” current-voltage dependences. It is shown that the elimination of the component of the tunneling current allows one to increase the efficiency of the Ge subcell by ∼1% with conversion of nonconcentrated solar radiation. The influence of the tunneling current on the efficiency of the Ge-based devices can be in practice reduced to zero at photogenerated current density of ∼1.5 A/cm² due to the use of the concentrated solar radiation.     

五结太阳能电池设计与模拟

设计了与太阳光谱更匹配的五结太阳能电池(Al)GaInP/AlGa(In)As/(In)GaAs/GaInAsN/Ge,并首次应用APSYS软件对其电特性进行了模拟。与四结太阳能电池和传统的InGaP/GaAs/Ge结构进行对比,结果表明该结构各结电流更加匹配,获得了较高的转换效率。