Microstructures and dielectric properties of compositionally graded (Ba1-xSrx) TiO3 thin films prepared by pulsed laser deposition

被引：0

作者：

X. Zhu

S. Lu

H.L.W. Chan

C.L. Choy

K.H. Wong

机构：

[1] National Laboratory of Solid State Microstructures,

[2] Department of Physics,undefined

[3] Nanjing University,undefined

[4] Nanjing 210093,undefined

[5] P.R. China,undefined

[6] Department of Applied Physics and Materials Research Center,undefined

[7] The Hong Kong Polytechnic University,undefined

[8] Hung Hom,undefined

[9] Kowloon,undefined

[10] Hong Kong,undefined

[11] P.R. China,undefined

来源：

Applied Physics A | 2003年 / 76卷

关键词：

PACS: 68.55.-a; 77.55.+f; 81.15.Fg;

D O I：

暂无

中图分类号：

学科分类号：

摘要：

Compositionally graded (Ba1-xSrx)TiO3 (BST) (x:0.0∼0.25) thin films were grown on Pt (111)/TiO2/SiO2/Si (100) substrates using layer-by-layer pulsed laser deposition in the temperature range 550–650 °C. Both downgraded (Ba/Sr ratio varying from 100/0 at the bottom surface to 75/25 at the top surface) and upgraded (Ba/Sr ratio varying from 75/25 at the bottom surface to 100/0 at the top surface) BST films were prepared. Their microstructures were systematically studied by X-ray diffractometry and scanning electron microscopy. A grain morphology transition from large ‘rosettes’ (>0.30 μm) to small compact grains (70–110 nm) was observed in the downgraded BST films as the deposition temperature was increased from 550 to 650 °C. No such grain morphology transition was detected in the upgraded BST films. Dielectric measurements with metal electrodes revealed an enhanced dielectric behavior in the downgraded films. This enhancement is mainly attributed to the large compressive stress field built up near the interface between the downgraded film and substrate. Furthermore, the BaTiO3 layer in the downgraded BST films not only serves as a bottom layer but also as an excellent seeding layer for enhancing the crystallization of the subsequent film layers in the downgraded films.

引用

页码：225 / 229

页数：4