Amorphous and crystallized Ge-Sb-Te thin films deposited by pulsed laser: Local structure using Raman scattering spectroscopy
Amorphous and crystallized Ge-Sb-Te thin films deposited by pulsed laser: Local structure using Raman scattering spectroscopy
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DOI：
10.1016/j.matchemphys.2012.08.024
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发表时间：
2012-10-15
影响因子：
4.6
通讯作者：
Frumar, M.
中科院分区：
文献类型：
--
作者：
Nemec, P.;Nazabal, V.;Frumar, M.
采用紫外脉冲激光沉积来制造非晶 (GeTe)(x)(Sb2Te3)(1) (x)。 (x - 1、0.66、0.5、0.33 和 0) 薄膜。使用拉曼散射光谱研究了沉积态（非晶态）和退火态（结晶态）层的局部结构。还记录了用于沉积的块体材料的拉曼光谱。在非晶 Ge-Sb-Te 薄膜中观察到的振动模式，除了有缺陷的八面体配位外，还归因于 GeTe4 Ge-n(n)（n = 1、2，最终为 0）共享角和/或边的四面体和 SbTe3 金字塔实体，后者在所有含有 Sb2Te3 的薄膜的拉曼光谱中占主导地位。结晶化的 GeTe 和 Sb2Te3 的结构类似于起始块体材料的结构，这可以通过菱形变形岩盐 GeTe 的 Gamma(3) (E) 和 Gamma(1) (A(1)) 模式以及六方 Sb2Te3 的 E-g (2) 和 A(1g) (2) 模式的存在来证明。我们认为，在结晶化的 Ge2Sb2Te5、Ge1Sb2Te4 和 Ge1Sb4Te2 薄膜中，拉曼活性特征可能归因于有缺陷的八面体局部结构和/或软化的 A、共角 GeTe4 四面体模式、共角 GeTe4 Ge-n(n) (n = 1,2) 四面体的 A(1) 模式、GeTe4F2 模式、Sb-Te 模式SbTe3 实体，最终为六方 Sb2Te3 的 E-g (2) 和 A(1g) (2) 模式。 (C) 2012 Elsevier B.V. 保留所有权利。
UV pulsed laser deposition was employed for the fabrication of amorphous (GeTe)(x)(Sb2Te3)(1) (x). (x - 1, 0.66, 0.5, 0.33, and 0) thin films. The local structure of as-deposited (amorphous) as well as annealed (crystallized) layers was studied using Raman scattering spectroscopy. Raman spectra were recorded on bulk materials used for the deposition as well. The vibrational modes observed in amorphous Ge-Sb-Te films are attributed, apart from defective octahedral coordination, to GeTe4 Ge-n(n) (n = 1, 2, eventually 0) corner- and/or edge-sharing tetrahedra and SbTe3 pyramidal entities, the latter dominated Raman spectra of all the films containing Sb2Te3. The structure of crystallized GeTe and Sb2Te3 resembled that of starting bulk materials which is evidenced by the presence of Gamma(3) (E) and Gamma(1) (A(1)) modes of rhombohedrally deformed rocksalt GeTe and E-g (2) and A(1g) (2) modes of hexagonal Sb2Te3. We propose that in case of crystallized Ge2Sb2Te5, Ge1Sb2Te4, and Ge1Sb4Te2 films, Raman active features might be attributed to defective octahedral local structure and/or softened A, mode of corner-sharing GeTe4 tetrahedra, A(1) mode of corner-sharing GeTe4 Ge-n(n) (n = 1,2) tetrahedra, GeTe4F2 mode, Sb-Te mode in SbTe3 entities, eventually E-g (2) and A(1g) (2) modes of hexagonal Sb2Te3. (C) 2012 Elsevier B.V. All rights reserved.