Electron doping of NdNiO3 thin films using dual chamber CaH2 annealing
Electron doping of NdNiO3 thin films using dual chamber CaH2 annealing
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DOI：
10.1016/j.jssc.2022.123512
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发表时间：
2022-08
影响因子：
3.3
通讯作者：
D. K. Amarasinghe;Haoming Yu;F. Rodolakis;Hua Zhou;Hui Cao;S. Ramanathan
中科院分区：
文献类型：
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作者：
D. K. Amarasinghe;Haoming Yu;F. Rodolakis;Hua Zhou;Hui Cao;S. Ramanathan
氢供体掺杂已被开发作为一种策略来操纵功能氧化物系统的电子结构和电学性质。特别是，考虑到丰富的电子相图托管几个功能特性，开发利用间隙氢实现钙钛矿稀土镍酸盐薄膜的电子掺杂的合成方法是非常可取的。在这项工作中，我们提出的NdNiO 3（NNO）薄膜的氢化使用CaH 2退火和氢化的NNO（H-NNO）薄膜的电阻率的巨大调制。采用磁控溅射法在LaAlO 3（LAO）单晶衬底上制备了存款厚度为60 nm的NNO外延薄膜。在500 °C下退火24 h后，实现了原始钙钛矿NNO相的形成。在280 °C下，在具有两个互连室的真空安瓿中进行NNO薄膜的CaH 2退火，持续时间为1至6 h。双室设计实现了一种简单、清洁的氢掺杂方法，粉末和目标样品之间没有物理接触。X射线衍射和拉曼光谱显示，在原始样品中形成NNO，和随后的氢掺入CaH 2退火后，没有形成任何杂质相。利用X射线光电子能谱和X射线吸收谱研究了CaH 2退火后Ni的氧化态向+2的转化。因此，在室温下的电阻率的大幅增加，观察到CaH 2退火后，表明形成了强相关的电子配置的Ni在H-NNO由于电子掺杂。总的来说，这项研究的结果突出了多功能性的CaH 2退火作为电子掺杂的方法来调整相关的氧化物在低温下的电性能。
Hydrogen donor doping has been exploited as a strategy to manipulate the electronic structure and electrical properties of functional oxide systems. Especially, the development of synthetic methods to achieve electron doping of perovskite rare-earth nickelate thin films utilizing interstitial hydrogen is highly desirable considering the rich electronic phase diagram hosting several functional properties. In this work, we present the hydrogenation of NdNiO3(NNO) thin films using CaH2annealing and the resulting giant modulation of electrical resistivity in hydrogenated NNO (H–NNO) thin films. Magnetron sputtering was employed to deposit epitaxial ∼60 nm-thin NNO films on single crystal LaAlO3(LAO) substrates. The formation of the pristine perovskite NNO phase was realized after annealing the films at 500 °C for 24 h. CaH2annealing of NNO thin films for time durations ranging from 1 to 6 h was performed in a vacuumed ampule with two interconnected chambers at 280 °C. The two-chamber design enables a simple and clean approach for hydrogen doping without physical contact between the powder and sample of interest. X-ray diffraction and Raman spectroscopy revealed the formation of NNO in pristine samples, and the subsequent hydrogen incorporation upon CaH2annealing without forming any impurity phases. The conversion of the oxidation state of Ni towards +2 upon CaH2annealing was probed using X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. Consequently, a substantial increase in the room-temperature resistivity was observed upon CaH2annealing indicating the formation of a strongly correlated electronic configuration of Ni in H–NNO due to electron doping. Overall, the findings of this study highlight the versatility of CaH2annealing as an electron doping method to tune the electrical properties of correlated oxides at low temperatures.