应用基于反应力场的分子动力学方法研究了ZnO薄膜(001)表面作为衬底的薄膜沉积生长过程,初步讨论了500K时,沉积速率(1.5、2.5和3.5m/s)变化对沉积薄膜质量的影响。结果表明沉积速率约3.5m/s时,衬底结构最稳定,沉积原子结构径向分布函数曲线特征峰尖锐、明显,有序度较高;每原子层密度分析表明优化的沉积温度和沉积速率下,沉积形成的薄膜结构稳定而又致密。在预置衬底表面平坦的情况下薄膜呈现一种岛状的生长模式,近衬底区Zn—O键呈现理想的生长取向,而近表面区则两种生长取向共存,导致其生长前锋交汇处形成新的有序缺陷及氧空位。
The understanding of the growth process and formation mechanism of ZnO film on the atomic scale is crucial in adjusting and controlling the film depositing conditions. Using the reactive force field based molecular dynamics method, we theoretically studied the effect of depositing velocity (1.5, 2.5 and 3.5m/s) on the quality of ZnO film with the temperature of 500K, and some results agree with the experimental observation. It is found that, when depositing velocity is 3.5m/s, the radial distribution function curve of the deposited structure are sharp and highly ordered, and the finally formed thin film possesses the most stable and ordered structure than the other conditions. The film grew with an island mechanism.