Epitaxial growth, structure, and intermixing at the LaAlO3/SrTiO3 interface as the film stoichiometry is varied
Epitaxial growth, structure, and intermixing at the LaAlO3/SrTiO3 interface as the film stoichiometry is varied
复制标题
DOI：
10.1103/physrevb.83.085408
复制
发表时间：
2011-02-11
影响因子：
3.7
通讯作者：
Chambers, S. A.
中科院分区：
文献类型：
--
作者：
Qiao, L.;Droubay, T. C.;Chambers, S. A.
采用离轴脉冲激光沉积技术在SrTiO3（001）衬底上生长出La:Al阳离子比为0.9 ~ 1.2的LaAlO3外延膜。虽然所有薄膜都是外延的，但摇摆曲线测量表明，晶体质量随着La: Al比的增加而下降。La: Al比分别为0.9、1.0和1.1的薄膜被相干应变到衬底上。然而，在这个范围内，面外晶格参数增加，表明薄膜的四边形减少。虽然所有薄膜表面都表现出羟基化，但富la薄膜的羟基化程度更大。卢瑟福后向散射光谱分析表明，薄膜中的La深入扩散到SrTiO3衬底中，二次离子质谱分析表明，Sr向薄膜中扩散。
LaAlO3 epitaxial films with La:Al cation ratios ranging from 0.9 to 1.2 were grown on TiO2-terminated SrTiO3 (001) substrates by off-axis pulsed laser deposition. Although all films are epitaxial, rocking curve measurements show that the crystallographic quality degrades with increasing La: Al ratio. Films with La: Al ratios of 0.9, 1.0, and 1.1 were coherently strained to the substrate. However, the out-of-plane lattice parameter increases over this range, revealing a decrease in film tetragonality. Although all film surfaces exhibit hydroxylation, the extent of hydroxylation is greater for the La-rich films. Rutherford backscattering spectrometry reveals that La from the film diffuses deeply into the SrTiO3 substrate and secondary-ion-mass spectroscopy shows unambiguous Sr outdiffusion into the films.