基于碳纳米管光致发光特性的光通信用新型光电器件研究

Semiconducting single-walled carbon nanotube (s-SWCNT) possesses unique linearly polarized photoluminescence properties, and s-SWCNTs of different chiralities differ much on the photoluminescence wavelengths. Based on these unique photoluminescence properties, we can fabricate micro-/nano-scale s-SWCNT-based photonics devices emitting linearly polarized light yield. However, the relatively low photoluminescence efficiency of SWCNT hinders its photonics applications, so how to improve this key parameter is currently a pressing key problem to be solved, which constitutes the sally port of this project study. In this project, we propose to firstly focus on the realization of multi-layer ultrahigh density axial alignment of SWCNT by dielectrophoresis, and then the introduction of gold nanolayer as the coupling source of the surface plasmon polariton, which are regarded as two ways of improving the photoluminescence efficiency of SWCNT film emitting linearly polarized light yield. Meanwhile, we also propose to study and reveal the physical mechanism of the photoluminescence efficiency enhancement induced by the coupling of gold nanolayer’s surface plasmon polariton, by using a novel scattering scanning near-field optical microscope and combining with the numerical simulation on COMSOL software. Finally, based on these two ways of enhancing photoluminescence efficiency of SWCNT film, we propose to realize SWCNT-based photoluminescence devices emitting linearly polarized light yield for photo-communication applications by micro-fabrication technology.

半导体型单壁碳纳米管的光致发光具有独特的线偏振特性，不同手性的半导体型碳纳米管发光波长不同，可基于其这些独特的光致发光特性制造线偏振光输出的碳纳米管微纳光电器件。然而，碳纳米管的较低发光效率限制了其在光电器件方面的应用，故如何提高这一关键参数成为了亟待解决的关键问题。以此关键问题为突破口，本项目拟首先致力于利用介电电泳技术实现多层超高密度轴向一致排列碳纳米管薄膜，然后引入金纳米层作为表面等离子体激元耦合源，通过该两种途径大幅提高碳纳米管薄膜的光致发光效率，实现线偏振光输出。同时，本项目拟利用散射型扫描近场光学显微镜这一新颖手段结合软件COMSOL数值模拟，研究和揭示金纳米层表面等离子体激元耦合提高碳纳米管薄膜光致发光效率的物理机制。最后，利用微加工技术实现基于该两种途径提高光致发光特性的可用于光通信领域的碳纳米管线偏振光致发光器件。

半导体型单壁碳纳米管是一种直接带隙的一维碳基半导体材料，不同手性的半导体型碳纳米管发光波长不同，其具有独特的线偏振发光特性。可基于其这些独特的光致发光特性制造线偏振光输出的碳纳米管微纳光电器件。同时，其作为一维量子线结构，可通过掺杂等途径对其能带和载流子密度等物理参数进行调控。本项目研究了利用改进的介电电泳技术来提高碳纳米管的定向一致排列密度，从而提高其薄膜的光学特性，同时，还研究了利用化学掺杂对其能带和载流子密度等物理参数进行调控后的表面等离激元特性。主要研究成果体现在以下两个方面：1）利用改进的介电电泳技术实现了碳纳米管定向一致排列密度提高至少400倍，并在该实验过程中发明一种新型的测量物质介电常数的方法和一种估算热对流过程中“对流力”的新方法；2）利用硝酸蒸汽对半导体型碳纳米管进行化学掺杂，通过利用SNOM对其表面等离激元的测量对比表明该掺杂方法有效调控了碳纳米管的能带结构和载流子密度。相应结果发表于Nanoscale、Nanoscale Research Letters和Journal of Luminescence等I或II区SCI期刊，此外，基于上述发明的两种方法，还有两项专利拟申请。上述研究成果为改善和调控碳纳米管及其薄膜和器件的物理特性提供了非常有价值的技术参考，发明的两种测量方法可作为主流测量方法很有意义的补充。