高品质柔性、透明2H-SiC纳米线薄膜的制备及其压电、电学特性研究

Although SiC has been applied commercially as working materials like in solid state lighting, the fabrication of large-scale crystal faces great difficulty. For nanowires, the situation is not very good either, because complex stacking faults always exist in nanowires, which make the relative device work far from the optimize performance. Actually, reasonable doping can induce SiC to grow dominated by wurtzite symmetry, and simultaneously suppress the emergence of intense SFs. Herein, we intend to realize optimized 2H-SiC nanowires with few SFs and investigate their physical properties. We also want to explore the precise atomic align near a SFs. Based on above effort, by referring to advanced micro-nano operation technology, the influence of SFs upon SiC nanowires device and possible mechanism would be investigated. Moreover, we would like to realize the self-assembly of flexible, transparent and self-standing 2H-SiC nanowires paper, also investigate the properties when bended and stretched. On the other hand, a single nanowire based device would be also investigated under types of strain. 2H-SiC nanowires are designed to be wrapped with SiO2 layer by simple thermal oxidation and ALD technology, in order to integrate the elasticity and plasticity in a single nanowire, which is expected to be endowed with viscoelasticity.

虽然SiC在固态光源等领域已经实现产业化，但高品质晶体制备的困难导致其成本、量产面临瓶颈。在纳米领域，由于高密度的堆垛层错（SFs）普遍存，对SiC纳米线器件的研究同样困难重重。本课题中，我们拟通过元素掺杂实现SiC生长的物相选择，并抑制层错的产生，进而制备高品质的2H-SiC纳米线；考察其I-V，FET等基本电学特性，利用原子力压痕法以及纳米线原位弯曲的方式进行压电特性测试，建立定量化模型进行阐述。借助先进的微纳操纵技术，实现单个纳米线在透射电镜，原子力显微镜，以及电学器件之间的原位、半原位研究，建立结构与物性之间的关联，探索SFs对物性的影响。另外，基于气流导向的纳米线自组装实现柔性、透明、自支撑的纳米线纸，并考察其形变状态下的电学特性。面向柔性器件应用，对纳米线的力学特性进行设计，采用表面氧化或者原子层沉积工艺制备SiC@SiO2一维结构，实现纳米线的粘弹性，进而增强其抗弯能力。

在项目执行期内，申请人针对碳化硅纳米线目前的一些瓶颈开展了系列研究，包括可控制备以及光电特性的相关研究，填补了纤锌矿碳化硅纳米线研究领域的空白，比如纯相无掺杂纳米线的可控制备，透明柔性纳米线薄膜光紫外电探测器等。针对其他重要硅基材料纳米线开展了自组装以及新物性设计的工作，包括硅纳米线薄膜的多时间尺度光电响应行为，具有优异光学以及力学特性的氧化硅气凝胶设计；为解决传统金属纳米线作为互联导线理化稳定性差的问题，提出熔融玻璃体中高温析出制备毫米级硅合金纳米电缆的新方法，应用在高温、酸性、氧化性环境中展现出高稳定性。针对重要宽带隙氧化物纳米线，开展了系列创新性研究，比如，基于色心动力学，发展了聚焦电子束诱导的色心晶体中原位高浓度色心产生，进而实现微区高分辨率光、电特性编码与擦除；提出梭形半导体纳米锥作为纳米波导可有效提升光束缚与传导能力，成功观测到紫外光纳米聚焦效应，为近场点光源提供新策略。在本项目的资助下，以第一/通讯作者在Nat.Comm., Nano Lett., ACS Nano等杂志发表研究论文多篇。