【作者】 陈威林；

【导师】 李润伟； 高双；

【作者基本信息】 中国科学院大学(中国科学院宁波材料技术与工程研究所) ， 材料物理与化学， 2020， 硕士

【摘要】 继石墨烯和过渡金属硫化物之后,黑磷（BP）成为新一代的层状半导体材料。由于具有带隙适中（0.3～2 e V）、载流子迁移率高(～1000 cm²V^-1s^-1)等半导体特性优势,黑磷在众多领域具有广阔应用前景,例如作为阻变功能层而应用于阻变存储器领域。值得注意的是,阻变存储器不仅具有高速、高密度、低功耗等优异性能,而且能够实现存算一体化,为构建高效能计算机提供了一条新思路。尽管如此,二维黑磷却很容易被氧化,从而失去其优异的半导体特性。基于上述背景,本论文以黑磷纳米片（BPNSs）的共价修饰和基于氧化还原机理的新型黑磷阻变存储器研发为中心,开展了BPNSs的液相剥离、三苯胺重氮盐（DTPA）的化学合成、黑磷纳米片的共价修饰（BPNSs-TPA）、BPNSs-TPA的抗氧化性与电化学活性表征、基于BPNSs-TPA的阻变存储器件搭建与测试等研究工作,主要研究进展可概括如下:首先,利用基于探针超声的液相剥离法制备出了较高质量的BPNSs,再结合利用重氮化反应合成的DTPA,二者通过亲核加成反应获得了三苯胺（TPA）共价修饰的BPNSs（BPNSs-TPA）,并利用多种表征手段对修饰效果进行了测定。结果表明,修饰后的BPNSs在形貌和晶格结构上都发生了一定程度的改变,抗氧化效果提高了5倍以上,并具有了显著提升的有机溶剂分散性和电化学活性。进一步地,利用BPNSs-TPA优良的半导体特性、空气稳定性以及电化学活性,搭建了基于BPNSs-TPA/EV（Cl O₄）₂氧化还原体系的阻变存储器。在电场作用下,利用TPA与EV（Cl O₄）₂之间的可逆氧化还原反应,实现对黑磷能带结构和输运特性的连续调控,从而使器件表现出电阻随电压非线性变化的阻变特性。测试结果表明,该器件的稳定擦写次数超过150次,数据保持时间超过2×10⁴s,展现出稳定的双极型非易失性阻变特性。与此同时,利用该器件进一步成功模拟了突触的兴奋和抑制功能,为黑磷在类脑神经计算中的应用提供了可能。更多还原

【Abstract】 Black phosphorus（BP）is a novel layered semiconducting material,bridging the energy band and carrier mobility gaps between graphene and transition mental dichalcogenides,which has broad prospects in optoelectronics and nanoelectronics,especially in the nonvolatile memory application.Resistive random access memories（RRAMs）not only are one promising candidate for the next-generation high-speed,high-density and low-power nonvolatile memory,but also can realize the merging of storage and processing functions,which provide a new idea for building high-performance computers in future.However,the contradiction of BP nanosheets（BPNSs）between excellent semiconductor properties and the disadvantage of easy oxidation is difficult to reconcile.Based on the above background,this thesis focuses on the covalent modification of BP via aryl diazonium to give BPNSs grafted with TPA molecules（BPNSs-TPA）and then the study of their potential application in redox-based RRAM device.The detailed works include the preparations of BPNSs and diazonium tetrafluoroborate of triphenylamine（DTPA）,covalent modification process to generate BPNSs-TPA,anti-oxidation capacity and electrochemical activity analyses of BPNSs-TPA,preparation and characterization of BPNSs-TPA-based memory device.The obtained resules are summarized as follows:Firstly,tip sonication was used to prepare high quality BPNSs.In combination with the successfully synthesized DTPA,diazotization reaction was used to prepare triphenylamine（TPA）covalently modified BPNSs（BPNSs-TPA）,which was confirmed definitely by various spectroscopic analyses.The results showed that the morphology and lattice structure of the modified BPNSs changed to some extent.Compared with the as-exfoliated BPNSs,BPNSs-TPA were found to exhibit a remarkable improvement of 5 times in the anti-oxidation capacity.More importantly,the distinct electrochemical activity and good dispersibility in organic solvents were also demonstrated in BPNSs-TPA.Secondly,as a proof of concept,the BPNSs-TPA has been further used as the key component to construct an air-stable analog redox resistive switching memory,showing promising applications not only as a bistable electronic device for data storage but also as an artificial synapse for neuromorphic computing.The prepared EV（Cl O₄）₂/BPNSs-TPA based memristor exhibited a nonvolatile rewritable performance with excellent endurance over 150 switching cycles and retention time over 20 thousand seconds.The potentiation and depression processes of a biological synapse was able to be simulated at the same time.These demonstrations provide a feasible new way to use organic molecules to protect and regulate the property of black phosphorus,which is of great significance in expanding the development of black phosphorus in synaptic simulation.更多还原