TiLixOy/石墨烯/SiC功函数调制及忆阻行为可控性研究

It is crucial to build the new generation of cognitive system that an electronic device similar to the feature of neuron synapse is successfully obtained. It is the most possible for a memristor to achieve this function for the novel memory device. In this project, Pt/TiLixOy/Graphene/SiC stack is fabricated and interfacial modulation as well as the controllability of its memristive behaviors will be investigated combined with plasma enhanced atomic layer deposition and RF assisted chemical vapor deposition based on our current research results. The Li ion which is similar to the properties between the neuron and synapse is choosed as the carrier. The TiO2 doped by Li ion denoted as TiLixOy thin films are fabricated by plasma enhanced atomic layer deposition. The concentration and distribution of Li ion in the films of TiLixOy is modulated. The interfacial layer of graphene with high thermal conductivity is obtained by epitaxial growth on the substrate via RF assisted chemical vapor depositiom at high temperature. The interficial barrier and work function of Pt/TiLixOy/Graphene/SiC stack will be modulated. The influence of interfacial thermal effect on the memristive behaviors is eliminated. It is helpful to optimize the electroforming step and modulate the memristive dynamical behavior of the oxide memristor. Furthermore, the controllability of the memristive behavior will be improved and the modulated mechanism of the memristive behavior will be charified. It is significant to develop the intelligent device similar to human brain and promote the progress of information technology.

获得具有神经突触功能的元器件是架构认知型计算系统的基础，而忆阻器是最有可能实现该功能的新型记忆器件。本课题拟在现有工作基础上，采用等离子体增强原子层沉积技术(ALD)与射频辅助高温化学气相沉积(CVD)工艺相结合，制备Pt/TiLixOy/石墨烯/SiC堆叠结构，开展其界面调制及忆阻行为可控性研究。选择与脑突触/神经元之间信息交换离子属性类似的Li离子作为载流子，利用ALD制备Li离子掺杂的TiO2薄膜(TiLixOy)，调控Li离子在TiLixOy薄膜中浓度及分布。通过射频辅助高温CVD系统在SiC衬底上外延生长高热导率/电导率石墨烯作为界面层，调节界面势垒及Pt/TiLixOy/石墨烯/SiC堆叠结构功函数，消除界面热效应对忆阻行为的影响，优化电形成过程与可控性，探讨离子型忆阻器记忆行为的调控机理。该研究对于开发类人脑智能器件，推动认知系统研究与信息技术发展具有重要意义。

在基金资助期间，项目组围绕该课题的主要研究任务开展了以下三方面研究： .一、.系统综述了石墨烯等二维材料中离子隧穿特性及其研究进展.二、.理论模拟了石墨烯等二维材料范德华异质结的电学特性，尤其是电导行为.三、.实验研究了锂离子氧化物/石墨烯基忆阻器的电学性质及其神经突触行为.基于上述研究工作，已发表SCI论文15篇，国家发明专利授权1项，培养博士后、博士、硕士研究生10人，本科毕业生6人，项目研究取得了明显进展，为氧化物忆阻器的神经突触行为和类脑智能器件的发展提供重要参考。