摘要
用直流反应溅射方法在Ｓｉ（１００）基片上生长出具有六角晶型的ＺｎＯ 薄膜．测量了样品的阴极射线发光特性及其与薄膜晶体结构的关系．在所有测量样品中均观察到较强的绿带（５２０ｎｍ ）发射，随着薄膜单晶程度的提高，光谱中开始出现蓝带（～４５０ｎｍ ），并在类单晶薄膜中看到了强度大于绿带的近紫外谱带（３９０ｎｍ ）；它的强度随着阴极射线电子束流密度增加而迅速增加．根据ＺｎＯ 中激子的结合能数据，推测紫带发射来源于ＺｎＯ 的激子跃迁．实验结果说明。
The cathodoluminescence of ZnO films deposited on Si substrates by reactive DC sputtering has been investigated.Comparing X\|ray diffraction patterns with cathodoluminescent spectra reveals the dependence of the luminescent spectrum on crystallinity of the ZnO films.For the ZnO films with high crystal quality,not only the characteristic green band(520nm)of ZnO but also the stronger ultraviolet(390nm)and the weak blue(430~460nm)bands have been observed.It is also found that the intensity of the ultraviolet band increases sharply with increasing the current density of cathode\|ray electron beam.The intensity of the green band becomes saturated at the same time.These results indicate that the ultraviolet band,which peak energy is 3 16eV,must be related to band\|gap transition of ZnO films.The exciton binding energy in ZnO is 60meV.So that the ultraviolet band,which energy is lower than the band gap of ZnO about 40meV,may correspond to the exciton emission.Thus the intensity of the ultraviolet band is able to much increase as long as the crystal quality of ZnO films is improved.Further experiments are needed to show the details of the energy levels of ZnO films.
