ABSTRACT
Abstract Effects and roles of the ZnO nucleation layers on Si substrates by introducing various deposition methods to properties of ZnO thin films grown by metalorganic vapor phase epitaxy (MOVPE) are investigated. Three different techniques were used to grow ZnO nucleation layers on Si, and then ZnO main layers were grown on these nucleation layers by MOVPE in the same growth condition. The MOVPE-grown ZnO film utilizing a ZnO nucleation layer grown by a plasma enhanced chemical vapor deposition technique on a Si (001) substrate showed high structural quality with the c-axis oriented crystallinity and optical property with the intensity ratio of the near band edge emission to deep level as about 665 in the photoluminescence even measured at room temperature. By this experiment we can speculate that the crystallinity of the buffer layer is greatly important to achieve the c-axis oriented main ZnO epitaxial layer with high qualities and that of the main layer is fairly related with the deep level emission which might be caused by oxygen vacancies or zinc interstitials. This fact indicates that a proper choice to ZnO buffer layers with high crystallinity can give high qualities to the ZnO epilayer.
