GaAs太阳电池空间质子辐射损伤的分子动力学研究

GaAs太阳电池在空间辐射条件下的性能衰减与电池内部微观结构紧密相关。文章针对空间辐射带质子辐照GaAs材料,利用分子动力学方法研究由被辐射材料中产生的不同能量(0.1~10 ke V)初级离位原子(PKA)引起的级联碰撞过程,分析缺陷随辐照时间、入射PKA能量的演化规律,探讨点缺陷和缺陷簇的形成特征。研究发现,在GaAs材料的缺陷对数目随时间的演化曲线中,在"离位峰"和稳定状态时,缺陷对数目与PKA能量呈一定的线性关系;PKA能量越高,辐射损伤越严重、越不易恢复,但缺陷复合率随能量升高趋于饱和;点缺陷在GaAs中主要以缺陷簇的方式存在,且随着能量的升高,孤立缺陷倾向于缔合成缺陷簇。

Molecular dynamics simulation on radiation damages of GaAs solar cells caused by spatial protons

The performance degradation of GaAs solar cells under the conditions of space radiation is closely related to the microstructure of the cells. Based on the molecular dynamics, this paper studies the collision cascade process caused by the PKA, generated by the protons in the spatial capture zone and with different energies(0.1 to 10 keV). We analyze the evolution of the defects against the time and the energy of the PKA, as well as the formation characteristics of the point defects and the defect clusters. A certain linear relationship is shown to exist between the number of Frenkel pairs and the PKA energies at the "displacement spike" and in the steady state; the higher the PKA energy is, the more serious the radiation damages will be, and the defects are harder to recover, but the recombination rate of the defects tends to saturate; the point defects in the GaAs exist mainly in the form of defect clusters, and with the increase of the PKA energy, the isolated defects tend to associate with the defect clusters.