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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。
A highly c-axis oriented MgZnO thin film was prepared on a Si (100) substrate using an excimer pulsed laser deposition (PLD) method. The morphology, structure, composition and optical properties of the films were characterized by SEM, XRD, XPS, PL and absorption spectra. It was found that the oxygen pressure has an important influence on the structure and optical properties of MgZnO films. When the pressure of oxygen increased from 5 Pa to 45 Pa, the PL peak of the PL spectrum shifted blue by 86 meV, which indicated that the increase of oxygen pressure increased the solubility of Mg in the MgZnO thin film. The films prepared at 15 Pa oxygen pressure show a unique, uniform hexagonal nanocolumnar structure with PL spectrum showing excellent luminescence properties, superior UV emission and faint visible luminescence under other preparation conditions. The emission of green light in the range of 500-600 nm, we discuss the mechanism may be derived from the oxygen-related defects in the deep level. The PLD was used to obtain the nano-columnar structure. The results show that the PLD can be used to prepare the epitaxial substrate of ZnO nano-array. The PLD technology can be used to develop high efficiency light-emitting devices based on ZnO nanostructures.