| AVS 55th International Symposium & Exhibition | |
| Electronic Materials and Processing | Tuesday Sessions |
| Session EM-TuA |
| Session: | Complex and Multifunctional Oxides |
| Presenter: | J.H. Liang, National Dong Hwa University, Taiwan |
| Authors: | J.H. Liang, National Dong Hwa University, Taiwan Y.J. Chen, National Dong Hwa University, Taiwan J.H. Du, National Dong Hwa University, Taiwan H.Y. Lai, National Dong Hwa University, Taiwan |
| Correspondent: | Click to Email |
ZnO is one of the potential candidates for application on the green light LED, since ZnO has a broad PL peak in the green light region. Since the green light emission is caused by defect level transition in ZnO, epitaxial relationship could affect the behavior of green light emission due to the formation of different types of defects. Therefore, we studied intensively the dependence of luminescence of the ZnO film on the epitaxial relationship between film and substrate in order to get high intensity of green light emission. In our experiment, we prepared ZnO thin films on sapphire substrates by metal organic chemical vapor deposition (MOCVD), using dimethylzinc (DMZn) and oxygen, respectively, as zinc and oxygen source. We changed the Ⅵ-Ⅱ ratios and the growth temperature, and annealed the ZnO thin film at various temperature of 600°C - 1000°C in three kinds of atmospheres (Argon, nitrogen and oxygen). We used XRD to analyze the crystal structure, PL to analyze light emission, FESEM to observe the morphology and TEM to observe the epitaxial relationship between the film and the substrate. We reported the successful growth of dense (002)-oriented ZnO thin films with nearly 100 nm of grain size. We found that the XRD intensity of (002) and the grain size of ZnO grown under all three kinds of atmospheres increase with increasing temperature. We also found that the intensity of UV and green light emission were the highest at 1000°C in oxygen atmosphere, and the improvement of the intensity of green light emission was even more significant. We suggested that the defects of oxygen dominate the intensity of green light emission. We will show the TEM results about epitaxial relation between the film and the substrate to prove that there are 30-degree rotated epitaxial relationship between the film and the substrate. We will discuss about how the epitaxial relationship may affect the green light luminescence.