【摘要】 以同步辐射真空紫外光 (1 95nm)为激发源 ,在低温下观察到Si基衬底上ZnO薄膜的发光有三种紫外发射 ,其峰值波长分别为 380 ,36 9.5 ,2 90nm。它们各自具有不同的衰减时间和不同的温度依赖关系 ,但其激发谱相同。强激发带不在近紫外区 ,而在真空紫外区 (1 0 0～ 2 0 0nm) ,可能源于ZnO的下价带 (Zn3d组态 )电子的激发。对三种紫外发射的来源作了分析讨论更多还原

【Abstract】 ZnO film has attracted more and more interest since its UV lasing was reported on "Science" (1997). A lot of sources, such as Xe lamp, YAG∶Nd laser and cathode ray, have been used as the excitation sources to investigate the luminescence of ZnO thin film. In the present work, synchrotron radiation light (VUV) of HASYLAB in Hamburg, Germany was applied to study the UV luminescence of ZnO thin film. The UV luminescence of ZnO thin film on Si substrate at different temperatures (7～300 K) were observed using synchrotron radiation light (195 nm) as excitation source. Its emission spectra include three different band peaking at 380, 369.5, 290 nm, respectively. Each of the three bands has different decay time and different temperature dependence, but they all have the same excitation spectra. The strong excitation band is in VUV range (100～200 nm) instead of near UV range. Combining the calculated results of ZnO electronic structure and experimental data, we suppose that the VUV excitation (6～10 eV) can be attributed to the excitation of electrons in the lower valance band of ZnO, which mainly consists of Zn3d states with bound energy from 4.0～6.5 eV. The origin of the three different UV emission bands was also discussed. 369.5 nm emission is from free exciton recombination, and 380 nm broad band is related to the inter band transition, while 290 nm emission may be corresponding to the recombination of the electron in the secondary energy well of the conduction band with the hole in the valance band, or may be come from structural defects.更多还原