氧气压强对PLD制备MgZnO薄膜光学性质的影响(英文)

使用准分子脉冲激光沉积(PLD)方法在Si(100)基片上制备了高度c轴取向的MgZnO薄膜。分别使用SEM、XRD、XPS、PL谱和吸收谱表征了薄膜的形貌、结构、成分和光学性质。实验发现氧气压强对MgZnO薄膜的结构和光学性质有重要影响。当氧气压强由5 Pa增大到45 Pa时,薄膜的PL谱紫外峰蓝移了86meV,表明氧气压强的增大提高了MgZnO薄膜中Mg的溶解度。在15 Pa氧气压强下制备的薄膜显示了独特、均匀的六角纳米柱状结构,其PL谱展示了优异的发光特性,具有比其他制备条件下超强的紫外发射和微弱的可见发光。500~600 nm范围内的绿光发射,我们讨论其机理可能源于深能级中与氧相关的缺陷。使用PLD得到纳米柱状结构表明:优化制备条件,可望使用PLD制备ZnO纳米阵列的外延衬底;可使用PLD技术开发基于ZnO纳米结构的高效发光器件。

Effect of Oxygen Pressure on the Optical Properties of MgZnO Films Prepared by PLD

MgZnO films with highly c-axis orientation have been prepared on silicon (100) substrates via the excimer laser PLD method. The morphologies, structures, components, and optical properties have been systemically characterized by SEM, XRD, XPS, PL and absorption measurements. It has been found the oxygen pressure plays an important role in determining the structure and optical properties of the MgZnO film. The film grown at 15 Pa exhibits a unique nanocrystal structure with very high optical quality. It has been found that the UV emission peak is blue-shift about 86 meV with the oxygen pressure increaseing from 5 to 45 Pa due to the increased solubility of Mg in MgZnO films. As for the green emissions located between 500~600 nm, they can be attributed to the deep-level emission of oxygen related defects. Our work will be of benefit to the further research to prepare epitaxial layer for growing ZnO nanoarrays by PLD technique.