【摘要】 利用低压金属有机化学气相淀积(LP MOCVD)在Si基片上外延生长ZnO薄膜,制备了两类样品一类是在Si上直接外延ZnO,另一类是在Si上通过SiC过渡层来外延ZnO.根据两类样品的拉曼光谱、x射线衍射、原子力显微图和光致发光的结果,表明ZnO外延薄膜中的张应力对薄膜的结晶状况有着重要的影响,使用SiC过渡层能够有效缓解ZnO薄膜中的张应力,减小缺陷浓度,提高ZnO外延层的质量;然后根据缺陷的形成机制进一步提出,对于ZnO Si,其中较大的张应力导致了高浓度的非辐射复合缺陷的形成,使得样品的紫外和绿峰的发射强度均大大降低;对于ZnO SiC Si,其中较小的张应力导致ZnO薄膜中主要形成氧替位缺陷OZn,从而使发光中的绿峰增强.更多还原

【Abstract】 High-quality ZnO films have been epitaxially grown on Si substrates by low-pressure metal organic chemical vapor deposition(LP-MOCVD) and two kinds of samples have been prepared:one is ZnO directly grown on Si while the other one grown with a SiC buffer layer.According to the results of Raman spectra,XRD,AFM,and photoluminescence,it is indicated that the tensile strain in the epitaxial ZnO films has a great influence on the crystalline quality of ZnO films,and the SiC buffer layer can effectively modulate the tensile strain,hence reduce the concentration of defects and improve the film quality.Then,from the defect formation mechanism,we suggest that for ZnO/Si,the large tensile strain results in high concentration of non-radiation recombination centers,which largely reduce the intensity of UV and green emissions; but for ZnO/SiC/Si,the small tensile strain results in oxygen antisite defects O-~Zn in ZnO films,which enhance the green emission in photoluminescence.更多还原