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研究了暴露在空气中退火和表面覆盖蓝宝石基板退火对MOCVD生长的ZnO薄膜光学性质的影响.研究发现,暴露在空气中退火虽可以去除薄膜中的氢杂质,并在低温光致发光(PL)谱中观察到与氢相关的束缚激子峰消失,但是退火后样品室温PL谱中可观察到很强的可见光发射,表明样品中引入了大量的深能级,样品的自由激子发光没有增强.而表面覆盖蓝宝石基板退火的样品,有效去除了氢杂质,但没有观察到可见光发射,说明表面覆盖蓝宝石基板退火可以有效地保护ZnO表面不分解,不生成深能级中心.由于激子束缚中心的减少,表面覆盖退火样品的自由激子发射大大增强.
The effects of annealing in air and surface-covered sapphire substrate on the optical properties of ZnO thin films grown by MOCVD were studied.The results showed that annealing in air could remove hydrogen impurities in thin films, and at low temperature photoluminescence (PL) Hydrogen-bound bound exciton peaks were observed to disappear, but strong visible light emission was observed in the PL spectrum at room temperature after annealing, indicating that a large number of deep levels were introduced into the sample and that the free exciton emission was not enhanced .The sample annealed on the sapphire substrate effectively removed hydrogen impurities but no visible emission was observed, indicating that annealing of the sapphire substrate can effectively protect the surface of ZnO from decomposing and not forming a deep level center.As the exciton binding center The free exciton emission of surface-covered annealed samples is greatly enhanced.