采用改变生长条件的方法制备GaN薄膜, 在(0001)面蓝宝石衬底上利用金属有机物化学气相沉积技术制备了不同样品, 并借助X射线双晶衍射仪(XRD)、PL谱测试仪和光学显微镜对材料进行了分析。XRD(0002)面和(1012)面测试均表明TMGa流量为70 cm3/min时样品位错密度最低。利用该TMGa流量进一步制备了改变生长温度的样品。XRD和PL谱测试结果表明, 提高生长温度有利于提高GaN样品的晶体质量和光学性能。最后, 利用光学显微镜对样品的表面形貌进行了分析。

GaN thin films were prepared by changing the growth condition. The epitaxial layers were grown by metal-organic vapor phase epitaxy on sapphire (0001) substrates, and were characterized by photoluminescence, optical microscope and X-ray double crystal diffraction. In the experiment, we used full width at half maximum of X-ray double crystal diffraction to detect the dislocation density, and found the samples dislocation density was lowest when TMGa flows at 70 cm3/min. Using the best value of TMGa flows, we grew the samples by changing the growth temperature. Photoluminescence spectra showed that higher growth temperature is conducive to improve the optical properties, reduce the Ga vacancies density in the GaN samples, and improve the quality of GaN crystal. Optical microscope test indicated that the increasing of the growth temperature will improve the surface morphology, it gives the same conclusion with photoluminescence spectra test.