【摘要】 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.更多还原

【Abstract】 ZnO films grown by metal organic chemical vapor deposition at atmospheric pressure are annealed at 850℃,with the film surfaces exposed to air or covered by a sapphire wafer.The optical properties of the as-grown and the annealed samples are studied by photoluminescence (PL) spectroscopy.It is found that the air-exposure annealing effectively removes the hydrogen impurities from the ZnO films but greatly increases the deep-level emission.In the surface-covered annealed sample,an elimination of the hydrogen impurities is also observed,and the deep-level emission disappears completely.The free exciton emission is significantly enhanced in the ZnO film after surface-covered annealing.更多还原