GaAsN/GaAs量子阱在1 MeV电子束辐照下的退化规律

为研究GaAsN/GaAs量子阱在电子束辐照下的退化规律与机制,对GaAsN/GaAs量子阱进行了不同注量(1×1015,1×1016 e/cm2)1 MeV电子束辐照和辐照后不同温度退火(650,750,850℃)试验,并结合Mulassis仿真和GaAs能带模型图对其分析讨论。结果表明,随着电子注量的增加,GaAsN/GaAs量子阱光学性能急剧降低,注量为1×1015 e/cm2和1×1016 e/cm2的电子束辐照后,GaAsN/GaAs量子阱PL强度分别衰减为初始值的85%和29%。GaAsN/GaAs量子阱电子辐照后650℃退火5 min,样品PL强度恢复到初始值,材料带隙没有发生变化。GaAsN/GaAs量子阱辐照后750℃和850℃各退火5 min后,样品PL强度随退火温度的升高不断减小,同时N原子外扩散使得样品带隙发生约4 nm蓝移。退火温度升高没有造成带隙更大的蓝移,这是由于进一步的温度升高产生了新的N—As间隙缺陷,抑制了N原子外扩散,同时导致GaAsN/GaAs量子阱光学性能退化。

Degradation of GaAsN/GaAs Quantum Well Under 1 MeV Electron Beam Irradiation

The radiation effects of MBE grown GaAsN/GaAs quantum well irradiated by 1 MeV electron with different dose(1×1015,1×1016 e/cm2)and post thermal annealing(650,750,850℃)have been studied.The degradation mechanism and annealing effects were discussed by Mulassis simulation and GaAs energy bandgap model.The results show that the GaAsN/GaAs quantum well PL intensity significantly decreased with the increase of electron does.The PL intensity of the GaAsN GaAs quantum well decayed to 85%and 29%of the initial value after electron irradiation with doses of 1×1015 e/cm2 and 1×1016 e/cm2,respectively.The PL intensity of GaAsN/GaAs quantum well returned to original value after annealing at 650℃for 5 min,and the bandgap of the material remained unchanged.The PL intensity of GaAsN/GaAs samples decreased as the annealing temperature increased after annealed at 750℃and 850℃for 5 min,and the bandgap blue shifted about 4 nm due to the diffusion of N atoms from GaAsN quantum well to GaAs barrier layer.The increase of annealing temperature did not cause additional blue shifts of the band gap.This was due to the further increase in temperature,which caused new N—As defects,suppressed N-atom diffusion,and degraded the optical properties of GaAsN/GaAs quantum well.