掺杂非晶碳薄膜/异质结在应力下的多场量子调控

This research was triggered by our recent observation of the strain induced photoconduction in doped amorphous carbon. Amorphous carbon doped by magnetic elements has demonstrated many superior properties such as positive colossal magnetoresistance (CMR) and electroresistance (ER) effects. Our preliminary results show a significant photoconduction on magnetically doped carbon. Such a photoconductance is strongly correlated with the strain applied. No photoconductive response could be found under zero strain. It was known that the strain could rarely affect amorphous system due to lacking of long-range ordering. Although the mechanism has not been well understood at this moment, it motivates and encourages a further in-depth study. .In this proposed project, our efforts will be focused on the metastability induced by strain in doped amorphous carbon. Various non-magnetic and/or rare earth metals will be used as the dopant. In-situ controllable strain can be introduced by employing the ferroelectric crystal of PMN-PT. Similar to the strain-mediated photoconduction, it may also induce some other fascinating features, which includes controlled switching of rich functionality such as ER and CMR. We will try to understand the underlying physics and explore the feasibility for using them to construct heterojunctions for sensors or photovoltaics.

最近我们在磁性掺杂的非晶碳低维材料中首次观察到显著的室温光电导。这一增强的光电导效应与外加于非晶碳的应力场直接相关，没有应力时几乎看不到任何光电导。因为不存在长程有序晶格的畸变，一般普遍认为应力场对于非晶材料的影响极其有限，故而应力场对非晶碳的调控鲜有报道。我们的结果显示应力场对于非晶碳基材料也同样具有很强的调控作用。本课题拟进一步探索应力场对碳基材料的宏观调制。鉴于磁性掺杂已被普遍研究，我们拟尝试将稀土或非磁性元素注入非晶碳，并采用压电性能优异的Pb(Mg1/3Nb2/3)O3-PbTiO3(PMN-PT)铁电晶体引入实时可控的应力场。在应力场下研究光、磁、电等外加物理场对掺杂非晶碳材料输运行为的微观量子调控，并系统关注应力对非晶碳体系呈现的其他亚稳特性如庞电致电阻和正磁阻效应的影响，实现对系统同时进行宏观和微观的多场调控。

本课题基本上是依照原来的研究设想按计划逐步展开实施。在前期工作的基础上，我们通过在氧化物压电晶体上沉积非晶碳薄膜来获得低维的异质复合体系。可控的应力场由氧化物铁电晶体的场致伸缩效应引入，同时引入光、磁、电等物理场，从微观和宏观尺度上系统研究应力场下的电磁耦合及量子调控效应，观察到非晶碳异质结的可变极性巨磁阻效应、亞稳的开关行为、自组装纳米粒子增强的光伏效应等有趣的科学现象。我们还原创发展了新颖的非晶碳/2DEG异质结和可穿戴的柔性非晶碳膜，并积极开展各种应用技术和先进微电子功能器件的开发。我们开发了柔性基底薄膜的制备与非晶碳/电子气异质结两项新工艺技术，探索设计了多种新型微电子器件,包括可穿戴的柔性碳基压力传感器件，基于非晶碳磁阻极性的可复写光信号存储元件，碳基RAM存储器件，高氧气相沉积样品加热装置，氢和NO2气敏探测元件等。为发展新一代的微纳传感器件和记忆元件开拓了新的领域。. 在本课题的实施中，我们取得了一系列突出成果，共发表标注本课题号的SCI高质量论文 31 篇，其中1篇文章被SCI列为高被引论文，短时间内已被引用超过75次。此外我们还申报了5项发明专利,1项新型实用专利已获授权。. 综上所述，本课题的各项目标均圆满达成，并在技术创新和产品开发有多项突破。