摘要
本文报道了用电子束热蒸发技术制备ZnO薄膜 ,薄膜具有 (0 0 2 )取向 ,通过电子扫描显微镜确认晶粒大小在 15 0nm左右 ,现有的薄膜在 5 2
Wide band gap semiconductor materials are of considerable interest for their important use in blue and ultraviolet optical devices such as light emitting diodes and laser diodes. In 1997 the ultraviolet laser emission of ZnO film at room temperature was reported.Then the random laser from nanosize ZnO power was also announced.After that this material has attracted a lot of scientists. And high quality ZnO films were grown by different methods such as MOCVD and MBE. We have obtained high quality ZnO films by reactive DC sputtering on Si (100) and Si (111) and observed its superlinear ultraviolet emissions.In order to compare the properties of ZnO films made by different methods,our team prepared ZnO films on Si (100) by electron beam evaporation.We wanted to gain polycrystalline films by this method.A serial of ZnO films has been obtained successfully by changing the speed of growth.All the samples were annealed in air at 950℃ for 1h. From the X ray diffraction pattern it was found that some films had very strong c axis orientation.But the orientation disappeared as the speed of growth became very high. The surface of film was observed by scanning electron microscope.From the picture one can see the crystallite grain with size around 150nm. At last the PL spectrum (210nm excitation) of the ZnO grain films was measured.The emission spectrum showed strong green band peaked at 525nm.The intensity increased with increasing the speed of growth.Because the high speed growth can create more defects,this result showed the emission of green light might be caused by defects. Recently, research efforts were usually focused on the blue emission and ultraviolet emission.We will try to obtain them by changing the conditions of growth and anneal of ZnO films.It was reported that the excitation spectrum of ultraviolet emission (390nm) peaked at 195nm.It's better to excite ZnO films with Synchrotron Radiation shorter than 200nm.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2001年第3期309-311,共3页
Chinese Journal of Luminescence
基金
自然科学基金资助项目 ( 5 9872 0 37)
