Defects in ZnO thin films grown on ScAlMgO4 substrates probed by a monoenergetic positron beam
Defects in ZnO thin films grown on ScAlMgO4 substrates probed by a monoenergetic positron beam
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DOI：
10.1063/1.1539915
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发表时间：
2003-03-01
影响因子：
3.2
通讯作者：
Koinuma, H
中科院分区：
文献类型：
--
作者：
Uedono, A;Koida, T;Koinuma, H
通过正电子湮灭对 ScAlMgO4 基底上生长的氧化锌 (ZnO) 薄膜进行了表征。我们测量了激光分子束外延沉积的ZnO薄膜和单晶ZnO的湮灭辐射的多普勒展宽光谱和光致发光光谱。尽管单晶ZnO中正电子的寿命接近于自由态湮灭的正电子的寿命，但正电子的扩散长度比典型无缺陷材料的扩散长度短。我们将此归因于固有缺陷导致的正电子散射。对于 ZnO 薄膜，我们观察到缺陷与束缚激子发射 tau(Ex) 的寿命之间的相关性；正电子湮灭检测到的主要缺陷种类是Zn空位或其他相关缺陷。研究发现，750-850℃的等时退火会在薄膜中引入额外的空位型缺陷，尽管退火几乎没有改变tau(Ex)的值。 (C) 2003 年美国物理研究所。
Zinc oxide (ZnO) thin films grown on ScAlMgO4 substrates were characterized by means of positron annihilation. We measured Doppler broadening spectra of annihilation radiation and photoluminescence spectra for the ZnO films deposited by laser molecular-beam epitaxy and single-crystal ZnO. Although the lifetime of positrons in single-crystal ZnO was close to the lifetime of positrons annihilated from the free state, the diffusion length of positrons was shorter than that for typical defect-free materials. We attribute this to the scattering of positrons by native defects. For the ZnO films, we observed a correlation between the defects and the lifetime of bound exciton emissions tau(Ex); the main defect species detected by positron annihilation was Zn vacancies or other related defects. Isochronal annealing at 750-850degreesC was found to introduce additional vacancy-type defects into the film, although the value of tau(Ex) was scarcely changed by the annealing. (C) 2003 American Institute of Physics.