射频磁控溅射ZnO薄膜的光致发光

Photoluminescence of ZnO Films Deposited on Si Substrate by RF Magnetron Sputtering

用射频磁控溅射法在硅衬底上沉积出具有良好的择优取向的多晶 Zn O薄膜 .在室温下进行光致发光测量 ,观察到明显的紫光发射 (波长为 4 0 2 nm )和弱的紫外光发射 (波长为 384 nm ) .紫光发射源于氧空位浅施主能级到价带顶的电子跃迁 ;紫外光发射则源于导带与价带之间的电子跃迁 .随着光激发强度的增加 ,紫光发射强度超线性增强 ,且稍有蓝移 ,而紫外光发光强度则近似线性增加 .在氧气中高温退火后 ,薄膜结晶质量明显提高 ,紫光发射强度变弱 ,紫外光发射相对增强 .

Highly orientated polycrystalline ZnO films are deposited on Si substrates at room temperature by using RF magnetron sputtering.A strong violet photoluminescence(PL) located at 402nm and a weak UV PL located at 384nm are observed when excited with 300nm light.The former PL originated from the electron transition from shallow donor levels of oxygen vacancies to the top of valence band and the later is generated due to electron transition from conduction band to valence band.With an increase in intensity of the excitation light,the violet emission peak increases super linearly and the UV emission increases linearly.After high temperature annealing in oxygen the crystallinity of obtained films is improved,the violet emission become weak and the UV emission gets strong.