稀土掺杂Ba0.6Sr0.4TiO3薄膜的介电及发光性能

以钛酸锶钡和稀土氧化物粉末靶为靶材, 用离子束溅射法在MgO(100)和Si(100)基片上组合制备了不同掺杂浓度的Ba0.6Sr0.4TiO3:Re(BST:Re)薄膜样品阵列. 沉积得到的多层无定形薄膜经低温扩散、高温晶化, 形成BST:Re多晶薄膜. 以扫描近场微波显微镜测定BST:Re/MgO(Re=Er, Eu, Pr/Al)样品的介电常数, 研究掺杂种类及掺杂浓度对BST薄膜介电常数的影响. 结果表明, 稀土离子的适量掺杂使BST薄膜介电常数有所提高, 其中, Er3+和Eu3+的最佳掺杂浓度分别为4.5%及5.7%(原子分数) 左右时, 介电常数值达到最高. 而共掺杂Pr3+和Al3+的样品则在n(AL):n(Pr)为4-8之间介电性能最佳. 另外, 测量了BST:Re/Si(Re=Er, Eu)样品的光致发光谱, 发现Er3+和Eu3+在BST薄膜样品中的发光猝灭浓度分别为4.20%和8.95%(原子分数).

Dielectric and Luminescent Properties of Rare Earth-Doped Ba0.6 Sr0.4 TiO3 Thin Films

Ba0.6Sr0.4TiO3:Re (BST:Re) thin films were synthesized by ion beam sputtering deposition. MgO(100) and Si(100) substrates were used for different measure requirements. The as-deposited multilayer films were transformed into polycrystalline films after two-step anealling-diffusion at lower temperature and crystallization at higher temperature. The dielectric constants of BST:Re/MgO(Re=Er, Eu, Pr/Al) samples were determined by a scanning tip microwave near-field microscopy. The results indicated that the dopings of appropriate amount of rare earth ions improved the dielectric constants, where the optimal doping concentratrations of Er3+ and Eu3+ ions were around 4.5% and 5.7%(atom fraction), respectively. The samples co-doped with Pr3+ and Al3+ got an optimum performance under 4-8 of Al/Pr molar ratio. We also investigated the photoluminescence properties of BST:Re/Si (Re=Er, Eu) samples. The luminescent quenching concentrations of Er3+ and Eu3+ ions doped in BST thin films were 4.20% and 8.95% (atom fraction), respectively.