石墨烯边缘嵌入式纳米薄膜的光电响应原理及其在传感器中的应用

2D material is a promising material for the next generation photo-electric sensor applied on wearable nano/micro mechantronic devices due to its unique photoelectric property. However, the role played by 2D material edge states in the photoelectric response is still overlooked and seldom investigated, hindering the development and application of novel photoelectric sensor. Recently, it was revealed that a kind of graphene-edge-rich nanofilm has the potential ability of high output and fast response, since the lowered edge potential wells formed in the nanofilm can serve as trapping centers of photo-excited electrons (also called “edge quantum well”), leading to the dramatically deduction of the electron-hole recombination rate. Hence, this project proposed and focused on the scientific problem - the principle of photoelectric response of graphene edge embedded nanofilm, and investigated it from three perspectives, i) the theory based on edge quantum well trapping of photo-electrons, ii) the technique testing the photosensing properties of different edge-density graphene edge embedded nanofilms, and, iii) the aim to acheive the nanofilm photoelectric sensor with high output and fast response. The results are of great scientific significance and of application value to enrich the conventional photoelectric response principle based on semiconductor theory and to explore the novel nanofilm photoelectric sensor modulated by edge quantum well.

二维材料因其独特的光电性能具有成为应用于可穿戴微纳机械设备的下一代光电传感器材料的潜力。然而，二维材料边界态在光电响应中所起的作用至今没有得到足够的重视和研究，这在很大程度上妨碍了新型光电传感器的实用化进程。申请人前期研究发现，在一种富含石墨烯边缘的纳米薄膜中，边界势能的降低形成了许多电子俘获中心（又称“边界量子势阱”），该势阱可大大减少光生电子-空穴对的再结合，因而使得这种新型纳米薄膜具有高响应输出和快响应速率等潜在特性。为此，本项目提出“石墨烯边缘嵌入式纳米薄膜的光电响应原理”这一核心科学问题，从石墨烯边界量子势阱俘获光电子原理出发，以不同石墨烯边缘密度下的纳米薄膜的光电响应特性测试为技术手段，以高输出快响应的纳米薄膜光电传感器器件化为目标开展三方面研究。研究结果对于丰富基于传统半导体理论的光电响应原理与开拓边界量子势阱调制的新型纳米薄膜光电传感器具有重要的科学意义与实用价值。

针对应用于可穿戴设备的下一代新型感光材料的开发，本项目以边界态在光电响应中所起的作用为出发点，深入研究石墨烯边界态在光电响应过程中所发挥的作用是提高新型传感器的光电响应特性。本项目针对“石墨烯边缘嵌入式纳米薄膜的光电响应原理”这一科学问题，从石墨烯边界量子势阱俘获光电子原理出发，以不同石墨烯边缘密度下的纳米薄膜的光电响应特性测试为技术手段，以纳米薄膜光电传感器的器件化为目标开展三方面研究。获得的主要研究成果如下：（1）利用含时密度泛函理论（TD-DFT）计算硅团簇-石墨烯纳米片的激发态光谱，揭示纳晶石墨烯边界量子势阱对光生电子的俘获原理。研究光子与石墨烯边缘嵌入式纳米薄膜中的电子之间的相互作用，揭示光电流的产生机理，阐明石墨烯边界量子势阱俘获光电子与电子-空穴对复合率降低之间的关系。（2）利用ECR制备生长了不同边缘密度的石墨烯边缘嵌入式薄膜，研究了偏置电压（20V、40V、60V、80V）对边缘密度结构的调制规律，分析了石墨烯边缘嵌入式薄膜的生长规律，揭示石墨烯边缘嵌入式纳米薄膜的光电响应原理。（3）实现石墨烯边缘嵌入式纳米薄膜/p型硅光电传感器、石墨烯边缘嵌入式纳米薄膜/n型硅光电传感器，通过定点转移技术搭建新型石墨烯边缘嵌入式纳米薄膜异质结高输出（0.401A/W）、快响应（260ns）的光电传感器，目前所制备的石墨烯边缘嵌入式纳米薄膜所能达到的最快响应时间可达纳秒级别。发表SCI论文11篇，其中中科院一区论文1篇，二区论文6篇。申请国家发明专利7项，其中3项已授权。研究结果对于丰富基于传统半导体理论的光电响应原理与开拓边界量子势阱调制的新型二维材料纳米薄膜光电传感器具有重要的科学意义与实用价值。