退火温度对PLD法制备ZnO:Eu3+,Li+薄膜结构和发光性质的影响

采用脉冲激光沉积(PLD)法在Si(111)衬底上制备了Eu3+,Li+共掺杂的ZnO薄膜,分别在450,500,550和600℃条件下进行退火,退火气氛为真空。利用X射线衍射(XRD)仪和荧光分光光度计研究了退火温度对薄膜结构和光致发光(PL)的影响。研究结果表明,Eu3+,Li+共掺杂的ZnO薄膜具有c轴择优取向,Eu3+,Li+没有单独形成结晶的氧化物,均以离子形式掺入ZnO晶格中。PL谱中有较宽的ZnO基质缺陷发光,ZnO基质与稀土Eu3+之间存在能量传递,但没有有效的能量传递。随着退火温度的增加,薄膜发光先增强后减弱,退火温度为550℃时发光最强。当用395 nm的激发光激发样品时,仅观察到稀土Eu3+在594 nm附近的特征发光峰,但发光强度随退火温度变化不明显。

Effect of Annealing Temperatures on Structure and Photoluminescence of Eu3+ and Li+Co-doped ZnO Films Deposited by Pulsed Laser Deposition

Eu3+ and Li+ co-doped ZnO films were prepared by pulsed laser deposition(PLD),and then annealed at different temperatures in vacuum.The films were characterized by X-ray diffraction(XRD) and photoluminescence(PL) spectra.The XRD patterns revealed that the ZnO:Eu3+,Li+ films were highly c-axis oriented and Eu3+ ions were successfully incorporated into ZnO crystals.The PL spectra of ZnO:Eu3+,Li+ films showed that the energy transferred from the host ZnO to Eu3+ was weak and ineffective.When excited at the wavelength of 325 nm,the emission spectra of all samples showed an UV band peaking at 390 nm and a wide band peaking at 470 nm,but no peaks appeared corresponding with Eu3+.With annealing temperatures increasing,the PL intensity increased at first and then decreased,and 550 ℃ is the best temperature for the samples annealed in vacuum.When excited at the wavelength of 395 nm,only a characteristic emission of 594 nm belonging to Eu3+ was observed,and with the annealing temperature increase,the peak intensity kept almost the same.