溅射制备纳米晶GaN∶Er薄膜的室温发光特性

Room temperature visible photoluminescence from nanocrystalline GaN∶Er film prepared by sputtering

利用直流磁控共溅射方法制备了GaN:Er薄膜.X射线衍射结果显示薄膜为纳米多晶结构,根据谢乐公式,计算得到了GaN薄膜晶粒的平均大小为5·8nm;透射电子显微镜结果显示为非晶基质中镶嵌了GaN纳米颗粒,尺寸在6—8nm之间;紫外可见谱结果表明在500—700nm的可见光范围内,薄膜的平均透过率大于80%,在紫外可见谱基础上,利用Tauc公式计算得到了纳米晶GaN薄膜的光学带隙为3·22eV;最后,测量了GaN:Er薄膜的室温光致发光谱,获得了Er3+离子在554nm处的强烈绿光发射.

GaN：Er thin film has been prepared by direct current （DC） planar magnetron reactive sputtering deposition. The film was characterized by X-ray diffraction （XRD）, ultraviolet—visible （UV—Vis） spectroscopy, transmission electron microscope （TEM） and photoluminescence （PL） spectroscopy, XRD shows the structure of the film was nano/poly-crystalline. The average grain size of the film was derived from XRD peaks using the Scherrer formula and the value was 5.8nm. TEM result indicated that the film was GaN nano-particles embed in amorphous matrix and the particle size was between 6—8nm. UV—Vis transmission spectrum shows that the transmission ratio of the film exceeds 80% in the visible zone from 500nm to 700nm. From UV-Vis spectrum, the optical band gap of the film was calculated using Tauc plot and the value was 3.22eV. Last, PL was measured by fluorescence spectrometer at room temperature and green emission of Er3＋ ions was clearly observed for the transition： 4S3/2（2H11/2）—4I15/2（554nm）.