Mo-Al co-doped VO2(B) thin films: CVD synthesis, thermal sensitive properties, synchrotron radiation photoelectron and absorption spectroscopy study
Mo-Al co-doped VO2(B) thin films: CVD synthesis, thermal sensitive properties, synchrotron radiation photoelectron and absorption spectroscopy study
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Mo-Al共掺杂VO2(B)薄膜：CVD合成、热敏特性、同步辐射光电子和吸收光谱研究
DOI：
10.1016/j.jallcom.2018.02.195
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发表时间：
2018-05-15
影响因子：
6.2
通讯作者：
Gao, Yanfeng
中科院分区：
文献类型：
--
作者：
Guo, Beibei;Wan, Dongyun;Gao, Yanfeng
赋予二氧化钒（VO2）薄膜优异的热敏性能非常适合在非制冷红外（IR）探测器中的应用。在这里，我们展示了一种共掺杂策略，通过使用简单可行的CVD方法来合成具有高温电阻系数（TCR，-3.6％/K）和良好的方块电阻（16.2 k Omega）的Mo-Al掺杂VO2（B）薄膜。 TCR和电阻均优于未掺杂和Al掺杂的VO2(B)薄膜，且TCR比Mo掺杂的VO2(B)薄膜大。性能改善的潜在微观机制可能是，与单一掺杂相比，Mo-Al 共掺杂由于尺寸和电荷补偿而产生更少的晶格变形、应变和载流子浓度不均匀性，以及共掺杂薄膜中 V4+-V4+ 对周围 3d 电子的部分释放。此外，单斜晶系(C2/m)VO2(B)特殊的二维八面体结构有利于掺杂的应变控制。这些薄膜采用基于同步辐射的 X 射线光电子能谱 (SRPES) 和 X 射线吸收近边缘结构 (XANES) 技术来研究 V 离子周围的局部原子和电子结构。结果表明，Mo和Al掺杂剂进入VO2晶格并占据了部分V晶格位置，导致V1-x-yMoxAlyO2取代固溶体的形成。 V L 边和 O K 边 XAS 结果相同地证实了 Mo-Al 共掺杂可能在薄膜中产生最小的晶格变形。因此，薄膜的高性能证明了共掺杂策略适用于非制冷红外探测器应用。 (C) 2018 Elsevier B.V. 保留所有权利。
Endowing vanadium dioxide (VO2) thin films with excellent thermal sensitive performance is greatly desired for application in uncooled infrared (IR) detectors. Here, we demonstrate a strategy of co-doping by using a simple and feasible CVD method to synthesize Mo-Al-doped VO2(B) thin films with high temperature-coefficient-of-resistance (TCR, -3.6%/K) and favorable square resistances (16.2 k Omega). Both the TCR and resistance are superior to that of undoped and Al-doped VO2(B) thin film, and the TCR is larger than that of Mo-doped VO2(B) thin film. The underlying microscopic mechanism for the performance improvement might be that Mo-Al co-doping creates less lattice deformation, strain and inhomogeneity of carrier concentration due to dimension and charge compensation than that of single-doping and the partly release of 3d electrons around V4+-V4+ pairs in co-doping films. Besides, the special two-dimensional octahedral structure of monoclinic (C2/m) VO2(B) favors the strain control with doping. The films have been subjected to synchrotron radiation based X-ray photoelectron spectroscopy (SRPES) and X-ray absorption near edge structure (XANES) techniques to study the local atomic and electronic structure around V ions. The results indicated that the dopants of Mo and Al were incorporated into the VO2 lattice and occupied some of the V lattice sites, resulting in the formation of the V1-x-yMoxAlyO2 substitution solid solution. V L-edge and O K-edge XAS results identically verified that Mo-Al co-doping might create the least lattice deformation in films. Hence, the high performance of films proves that the co-doping strategy is suitable for uncooled infrared detector applications. (C) 2018 Elsevier B.V. All rights reserved.