磁控溅射制备ZnO:Eu薄膜发光性能研究

Fabrication of Eu-doped ZnO thin films by magnetron sputtering and photoluminescence properties

采用射频磁控溅射法在蓝宝石基片上制备ZnO:Eu薄膜,通过X射线衍射仪和荧光分光光度计等测试其晶体结构和发光特性,分析退火对薄膜晶体结构和发光特性的影响。结果表明,ZnO:Eu薄膜为C轴择优生长的多晶薄膜,实现ZnO基质中掺杂Eu3+;退火样品结晶质量较好,有助于ZnO:Eu薄膜中Eu3+的5D0-7F2的能级跃迁发光;高于ZnO带隙的高能激发(间接激发)和Eu3+的7F0-5L6和7F3-5D2能级间的低能共振激发(直接激发)都能观察到Eu3+的5D0-7F2能级跃迁的特征发光(618nm);间接激发时存在ZnO基质与Eu3+之间发生能量传递。

The ZnO： Eu films grown by radio frequency （RF） magnetron sputtering on sapphire substrates were investigated. The lattice structure and photolumineseence （PL） properties of the ZnO：Eu films were ＇characterized by X-ray diffractometer and spectrometer,respectively. Influence of annealing on the lattice structure and PL properties of the ZnO：Eu films were analyzed. The results reveal that the ZnO：Eu films are polycrystalline with a C-axis oriented wurtzite structure. Annealing is beneficial to improve the crystallization quality and the intra-4f shell transition of 5D0-7F2 in Eu3＋. In PL measurements under the high-energy excitation above the band-gap energy of ZnO （indirect-excitation） and under the low-energy excitation resonant to the energy levels of 7F0-SL6 and 7F3-SD2 transitions （direct-excitation） , the annealed samples showed the red-emission lines （618nm） due to the intra-4f shell transition of 5D0-7F： in Eu3＋. There is energy transfer from ZnO to Eu3＋ under the indirect-excitation.