一维Mn^(2+)掺杂CdS纳米晶体的水热合成及其发光性能

用水热方法合成了一维Mn2+掺杂CdS纳米晶体。产品分别用SEM,EDS,XRD,TEM,HRTEM和PL等技术进行了表征。结果表明,掺杂Mn2+完全替代了CdS晶格中Cd2+的位置,产品具有较好的结晶性。荧光光谱中,CdS纳米晶体表面缺陷态的发射峰被完全抑制,只能观察到单一的Mn2+的发射峰。

基于SOI的一维光子晶体纳米梁腔电光调制器

随着光通信和光互联的高速发展,研究调制速率高、器件尺寸小且易于集成的电光调制器具有重要意义。提出了一种基于Si绝缘体材料(silicon-on-insulator,SOI)的一维光子晶体纳米梁腔(photonic crystal nanobeam cavity,PCNC)侧耦合电光调制器。根据时域耦合模理论,通过主线波导与一维光子晶体纳米梁腔形成侧耦合结构。采用圆柱型渐变孔径的一维光子晶体纳米梁腔,使光束更好的束缚在腔内,调整纳米梁腔的结构参数,使其工作在通信波段波长。同时,根据自由载流子色散效应,在纳米梁腔两侧引入掺杂形成p-n结,施加较低偏压调节纳米梁腔的谐振波长,从而实现对工作波长光信号的"通""断"调制。应用三维时域有限差分法(3D-finite difference time domain,3D-FDTD)对调制器光学特性和电学性能进行仿真分析。结果表明,该电光调制器可以实现波长为1550.55 nm的光信号调制,调制电压仅为1.175 V,插入损耗为0.04 dB,消光比为18.2 dB,尺寸仅为25μm^(2),调制速率为8.3 GHz,调制带宽可以达到90 GHz,可应用于集成光子器件及高速光通信领域。

Synthesis, properties and applications of one- and two- dimensional gold nanostructures

The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and dimensionality. Especially, anisotropic gold nanocrystals, such as nanowires, nanobelts, nanoplates and nanosheets, have attracted much attention due to their striking properties and promising applications in electronics, catalysis, photonics, sensing and biomedicine. In this review, we will summarize the recent developments of one- dimensional （1D） and two-dimensional （2D） gold nanostructures. Various kinds of synthetic methods for preparation of these 1D and 2D gold nanocrystals will be described. Moreover, we will also briefly introduce the properties and potential applications of these 1D and 2D gold nanocrystals.