Abstract
Artificial modulation of electronic structures and control of the transport dynamics of carriers and excitons in CdSe nanowire are important for its application in optoelectronic nanodevices. Here, we demonstrate the aggregative flow of excitons by bending CdSe nanowires. The bending strain induces spatial variance of bandgap, and the energy bandgap gradient will result in the flow of excitons towards the bending outer edge of CdSe nanowire. The exciton emission energy shows a uniform redshift in the bending region due to the aggregative flow of excitons, and the energy redshift increases linearly with increasing the strain at the outer edge of the CdSe nanowire. Our results show an effective method to drive, concentrate, and utilize the excitons in CdSe nanowires, which provides a guide for the design of high performance and flexible optoelectronic nanodevices.
摘要
调制CdSe纳米线的电子结构和发光性质对于进一步开发其在光电子功能器件中的应用具有十分重要的意义. 本研究揭示了弯曲CdSe纳米线中激子流的汇聚效应. 弯曲形变在CdSe纳米线中形成从弯曲内侧到弯曲外侧连续变化的带隙, 从而激子在能量梯度诱发的等效内建场的驱动下向较低能量的弯曲外侧漂移和汇聚. 由于激子迁移到弯曲外侧边缘并复合发光, 使得激子发光光谱在弯曲横截面发生整体红移, 并且发光能量的红移量随弯曲外侧边缘的最大拉伸应变线性增加. 本文展示了一种新的驱动、 汇聚乃至利用CdSe纳米线激子的有效方法, 对于开发和设计高性能的柔性光电子器件具有重要的指导意义.
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Xuewen Fu received his BSc degree (2009) in physics from Beijing Normal University and PhD degree in physics from Peking University in 2014. He spent half a year working as an exchange scholar at the Quantum Optoelectronic Laboratory, École Polytechnique Fédérale de Lausanne (EPFL). His current research interests include electronic-mechanical coupling and photoelectronics of micro/nano-semiconductors, as well as ultrafast photocarrier (exciton, electron and hole) transport and structural dynamics in novel nanostructures and applications.
Zhi-Min Liao received his BSc degree from Sun Yat-sen University in 2002 and PhD degree from Peking University in 2007. Thereafter, he joined the School of Physics at Peking University as a Lecturer and then became an associate professor in 2011. Meanwhile he spent one year working as a postdoctoral fellow in Trinity College Dublin. His current research is focused on quantum transport in semiconductor nanowires, graphene, topological insulators, and atomically layered materials.
Dapeng YU is a professor of School of Physics, Peking University. He received his BSc from East-China University, Shanghai, MSc at the Shanghai Institute of Ceramics, Chinese Academy of Sciences, and PhD from Laboratire de Physique des Solides, Université Paris-sud, Orsay, France. His research interests include developing controllable methods to fabricate semiconductor nanowires, exploring their properties and tunability, and applications in novel energy; quantum transport in graphene and other 2D materials; nano-electromechanical devices and sensing; solid-state nanopore sequencing.
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Fu, X., Liao, ZM., Ye, Y. et al. Outermost tensile strain dominated exciton emission in bending CdSe nanowires. Sci. China Mater. 57, 26–33 (2014). https://doi.org/10.1007/s40843-014-0002-y
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DOI: https://doi.org/10.1007/s40843-014-0002-y