空间用高效四结太阳电池器件及辐射加固方法研究

High efficiency and high radiation resistance are the new requirements for space power devices in nowadays rapid development of space technology. Although GaInP/GaAs/Ge multi-junction solar cells have been applied various space applications currently, it became very difficult to increase its efficiency due to the lattice mismatch and energy mismatch issues of solar cell structure designing. The purpose of this project is to solve the material grow difficulties in four-junction solar cell fabrication; to realize photo-current matched high efficiency radiation hardened full spectrum GaInP/GaAs/InGaAsP/InGaAs four-junction solar cell device; to study the effects of hetro-junction bandgap energy, carrier transportation mechanism, and surface energy states to solar cell performance by applying various nano scale measurement methods. These objectives will be achieved by applying radiation harden InP solar cell design techniques, combining two lattice mismatched solar cells by advanced highly controllable wafer bonding technology. By studying and analyzing the correlations between the solar cell fabrication parameters and radiation effects of solar cell under different irradiation sources, the radiation damage mechanism of the solar cell structure will be investigated and available methods for radiation hardening will be studied. The results of this project will provide invaluable information for designing future new type optoelectronic devices and promoting its space application.

空间和航天技术的飞速发展，对空间能源器件的效率及耐辐照性能等提出了更高的要求。目前，GaInP/GaAs/Ge三结太阳电池被广泛应用在各类空间任务中。但晶格失配和能量失配的限制，使得其效率的进一步提升变得非常困难。本项目针对目前四结结构太阳电池制备中的材料生长难题，基于耐辐照InP基太阳电池的设计制备，通过可控的高性能键合工艺将不同衬底生长的不同带隙能量的太阳电池结合，实现光电流匹配的高效宽光谱耐辐照GaInP/GaAs/InGaAsP/InGaAs四结太阳电池器件；发展纳米尺度光电扫描探针太阳电池界面表征方法，研究界面能带结构、载流子扩散、表面态等对电池效率的影响；分析太阳电池生长工艺及制备技术对其辐射效应的影响，获得四结宽光谱太阳电池结构与辐射损伤的相关性，揭示宽光谱太阳电池器件的辐射损伤机理，实现抗辐射加固。本项目的顺利开展对于促进未来先进光电子技术在空间领域的应用具有重要意义。

本项目通过分子束外延（MBE）技术探究了四结键合电池中的电流匹配设计，为实现高效抗辐照GaInP/GaAs//InGaAsP/InGaAs四结电池做了初步探索。通过室温晶片键合的方法将GaAs衬底上的GaInP/GaAs 双结电池和InP衬底上的InGaAsP/InGaAs双结电池键合成一单片集成四结太阳电池，有效解决了晶格失配的问题，实现了一个太阳强度下33%、聚光下大于42%的电池效率。针对高效GaInP/GaAs/InGaAsP/InGaAs四结电池在空间应用中的辐射效应，开展了键合四结太阳能电池及其子电池在不同宇宙射线辐射条件下的辐射效应研究，分析了不同能量、不同类型粒子在多器件中的输运情况，对其光学、电学参数进行了辐照前后的测试表征。通过大量辐照试验和对电池结构的优化，获得了四结宽光谱太阳电池生长和制备工艺与其辐射损伤关系及辐射损伤规律；揭示了四结宽光谱太阳电池和器件结构的辐射损伤机理，获得了抗辐射加固的方法和途径。本项目研究成果对新一代高效耐辐照宽光谱太阳电池器件的设计奠定了基础，在航天和国防领域中的电源系统具有很大的应用前景。