金属氧化物准一维纳米结构阻变机制与忆阻性能调控研究

With the feature size of electronic devices entering into the nanoscale regime, the migration of ions, trapping/detrapping of carriers and thermal effect induced by external bias voltage will result in reversible resistance switching in nanoelectronics devices and then hysteretic current-voltage behavior. Based on memristor, it is expected to achieve ultra-high density storage, computing and storage integration and artificial neural networks. However, despite resistance switching having been observed in nanodevices based on all kinds of materials, it’s potential applications will be restricted because of its unclear microscopic mechanism and unstable performance. Therefore, design and fabrication of nanoscale electronic devices with new structures and new functions based on electron, ion-coupled transport have become challenges and opportunities for future information technology. In this research proposal, based on quasi-one-dimensional chromic WO3 systems we aim to study the mechansims of electron and ion coupled transport; to clarify the effect of the ion transport, self-trapping carrier injection and Joule heat and the details of electrochemical redox reactions near the interface; to elucidate the effect of lattice structures, thermal effect and electric field on resistance switching, and then to realise effective regulation on memristive properties of nanodevices based on quasi-one-dimensional WO3 systems. Ultimately, we hope to put forward prototypes of nanoelionics devices with reversible, reliable and controllable memristive properties.

随着电子学器件特征尺寸进入到纳米尺度领域，外加偏压所激发的离子效应、电子效应和热效应足以导致器件的电学性能发生显著变化而具有忆阻效应。基于忆阻效应有望实现超高密度存储、计算和存储融合、以及人工神经网络。然而，尽管忆阻效应广泛存在于不同材料体系的纳米器件中，但由于其微观机制不清楚、忆阻性能不稳定而制约其应用前景。因此，在纳米尺度内基于电子、离子耦合输运设计、构筑新型电子器件已成为新的挑战和机遇。本项目旨在基于易变色的WO3体系准一维纳米结构，系统研究外场下电子与晶格孔道中离子的耦合输运机制，阐明离子输运效应、自束缚载流子注入效应和电极附近电化学氧化还原反应细节等，揭示晶格结构、热效应和场效应等对忆阻效应的影响，从而实现对准一维纳米结构中忆阻性能的有效调控。在此基础上构筑忆阻性能稳定、可调控的新型忆阻器件原型。

基于忆阻效应有望实现超高密度存储、计算和存储融合、以及人工神经网络，但由于其微观机制不清楚、忆阻性能不稳定而制约其应用前景。本项目基于具有离子易于迁移的一维孔道的WO3体系准一维纳米结构，在纳米尺度内研究电子、离子耦合输运、实现对准一维纳米结构中忆阻性能的有效调控。系统研究了WO3体系准一维纳米结构可控制备、Au/WO3准一维纳米结构/Au器件电输运性能和忆阻性能调控。获得了单分散性好、横向尺度可控的WO3、WO3-x和MxWO3(M = H+、Li+、Na+和K+等)纳米线。发现了通过外加偏压调控碱金属离子在一维晶格孔道中可逆、可重复漂移，以及与电子耦合输运，可以实现界面势垒诱导和局域态填充释放诱导两种阻变机制调控。发现了通过偏压扫描、光照调控水氧化氢离子表面格罗特胡斯机理漂移和晶格注入，实现器件忆阻性能显著提升和绝缘体-金属转变，从而实现从模拟型、数字型阻变效应调控。光激发调控WO3准一维纳米结构表面水氧化氢离子，可实现正负光电导转换，同时基于阻变与色变，构筑新型忆阻器件原型。进一步阐明了氧空位在忆阻性能中的作用机理：在低氧空位浓度下，WO3纳米线导电机制遵循SCLC 机制，并呈现出双极性忆阻性能；在高氧空位浓度下，WO3纳米线导电机制由缺陷导致晶格的强无序诱发安德森局域控制，呈现出单极性忆阻性能。我们的研究工作，对阐明阻变机制、调控阻变性能和构筑新型阻变器件原型具有重要科学意义。与此同时，基于金属氧化物低微结构，成功把不同性质的低维半导体材料层间堆叠形成新的人工结构，进一步丰富了其性能和器件功能，从而有望在高性能柔性光电探测、超薄柔性薄膜晶体管、发光二极管和光解水新型能源等领域获得潜在应用。