射频磁控溅射法制备ZnO薄膜的发光特性

利用射频磁控溅射法在硅衬底上制备出具有（002）择优取向的氧化锌薄膜，用波长为300nm的光激发，观察到在446nm处有一强的光致发光峰，它来自于氧空位浅施主能级上的电子到价带上的跃迁。并讨论了发光峰与氧压的关系以及退火对它的影响，且给出了解释。

Luminescence Properties of ZnO Films Prepared by r. f. Magnetron Sputtering

ZnO thin films with a strong c-axis orientation have been successfully deposited on Si substrate at room temperature (RT) by using JPGF-450 r. f. magnetron sputtering system. A sintered ceramic ZnO target with 99.99% purity was used as source material. A mixture of Ar (99.999%) and O 2 (99.999%) were used as sputtering gases. The argon and oxygen were introduced via two separately controlled leak valves so that the partial pressure could be adjusted. During film deposition, the argon partial pressure maintained at 1Pa, and the oxygen partial pressure maintained at 0, 2 and 5.2Pa respectively for different samples. The sputtering r. f. power was 200W and sputtering time was 20 minutes. The ZnO films were grown with argon partial pressure of 1Pa and oxygen partial pressure of 0, 2 and 5.2Pa, respectively. The XRD spectra revealed that all samples were polycrystalline and had a preferred orientation with c-axis perpendicular to the substrates. All samples show typical luminescence behavior with a narrow 446nm (2.78eV) emission peak when excited with 300nm light. The intensity of the PL peaks is found to be strongly dependent on the oxygen pressure during films deposition. As the oxygen partial pressure increase, the PL intensity decreases quickly. The blue emission is also affected by annealing in different ambient. For the vacuum annealed sample, the intensity of PL increases markedly. On the contrary, for the samples annealed in oxygen, the PL intensity decreases. The experiments prove that the luminescence emission peak located at 446nm corresponds to the electron transition from the shallow level of oxygen vacancy to valence band.