Growth of nanoporous high-entropy oxide thin films by pulsed laser deposition
Growth of nanoporous high-entropy oxide thin films by pulsed laser deposition
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DOI：
10.1557/s43578-021-00473-2
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发表时间：
2022-01
影响因子：
2.7
通讯作者：
H. Guo;Xin Wang;A. Dupuy;J. Schoenung;W. Bowman
中科院分区：
文献类型：
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作者：
H. Guo;Xin Wang;A. Dupuy;J. Schoenung;W. Bowman
高熵氧化物（HEO）具有熵稳定性和组成灵活性，在电池和催化领域有着巨大的应用潜力。本文采用脉冲激光沉积（PLD）技术，以岩盐（Co0.2Ni0.2Cu0.2Mg0.2Zn0.2）O陶瓷为靶材，制备了HEO薄膜。该膜表现出目标的晶体结构，是化学均匀的，并具有三维（3D）的岛屿形态与连接随机形状的纳米孔。系统地研究了PLD激光能量密度对晶体结构和形貌的影响。增加能量密度有利于在低衬底温度（300 °C）下的膜结晶，并增加膜厚度（60-140 nm）。柱状晶粒，岛（平均尺寸为19 nm至35 nm），和纳米孔（平均尺寸为9.3 nm至20 nm）的横向尺寸随着能量密度（3.4至7.0 J/cm 2）的增加而增加，解释为吸附原子的动能增加和沉积和扩散之间的竞争。此外，增加通量减少了在膜表面上观察到的不期望的液滴的数量。纳米多孔HEO膜具有可调的表面积和优异的相稳定性，可作为电化学反应界面。
High-entropy oxides (HEO) with entropic stabilization and compositional flexibility have great potential application in batteries and catalysis. In this work, HEO thin films were synthesized by pulsed laser deposition (PLD) from a rock-salt (Co0.2Ni0.2Cu0.2Mg0.2Zn0.2)O ceramic target. The films exhibited the target’s crystal structure, were chemically homogeneous, and possessed a three-dimensional (3D) island morphology with connected randomly shaped nanopores. The effects of varying PLD laser fluence on crystal structure and morphology were explored systematically. Increasing fluence facilitates film crystallization at low substrate temperature (300 °C) and increases film thickness (60–140 nm). The lateral size of columnar grains, islands (19 nm to 35 nm in average size), and nanopores (9.3 nm to 20 nm in average size) increased with increasing fluence (3.4 to 7.0 J/cm2), explained by increased kinetic energy of adatoms and competition between deposition and diffusion. Additionally, increasing fluence reduces the number of undesirable droplets observed on the film surface. The nanoporous HEO films can potentially serve as electrochemical reaction interfaces with tunable surface area and excellent phase stability.