Tsai Jing-Yuan, Chen Jui-Yuan, Huang Chun-Wei, Lo Hung-Yang, Ke Wei-En, Chu Ying-Hao, Wu Wen-Wei
Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
Department of Materials Science and Engineering, National United University, Miaoli, 360, Taiwan.
Adv Mater. 2023 Oct;35(41):e2302979. doi: 10.1002/adma.202302979. Epub 2023 Sep 1.
The application of high-entropy oxide (HEO) has attracted significant attention in recent years owing to their unique structural characteristics, such as excellent electrochemical properties and long-term cycling stability. However, the application of resistive random-access memory (RRAM) has not been extensively studied, and the switching mechanism of HEO-based RRAM has yet to be thoroughly investigated. In this study, HEO (Cr, Mn, Fe, Co, Ni) O with a spinel structure is epitaxially grown on a Nb:STO conductive substrate, and Pt metal is deposited as the top electrode. After the resistive-switching operation, some regions of the spinel structure are transformed into a rock-salt structure and analyzed using advanced transmission electron microscopy and scanning transmission electron microscopy. From the results of X-ray photoelectron spectroscopy and electron energy loss spectroscopy, only specific elements would change their valence state, which results in excellent resistive-switching properties with a high on/off ratio on the order of 10 , outstanding endurance (>4550 cycles), long retention time (>10 s), and high stability, which suggests that HEO is a promising RRAM material.
近年来，高熵氧化物（HEO）因其独特的结构特性，如优异的电化学性能和长期循环稳定性，而备受关注。然而，电阻式随机存取存储器（RRAM）对高熵氧化物的应用尚未得到广泛研究，基于高熵氧化物的RRAM的开关机制也有待深入探究。在本研究中，具有尖晶石结构的HEO（Cr，Mn，Fe，Co，Ni）O外延生长在Nb:STO导电衬底上，并沉积Pt金属作为顶部电极。经过电阻切换操作后，利用先进的透射电子显微镜和扫描透射电子显微镜对尖晶石结构的一些区域转变为岩盐结构进行了分析。从X射线光电子能谱和电子能量损失谱的结果来看，只有特定元素会改变其价态，从而产生了优异的电阻切换特性，开/关比高达10左右，出色的耐久性（>4550次循环）、长保持时间（>10 s）和高稳定性，这表明高熵氧化物是一种很有前景的RRAM材料。
