摘要:
二硫化钼(MoS2)是一种层状的二维过渡金属硫族化合物材料，从块体到单层，禁带由间接带隙变为直接带隙，由于通常机械剥落的单层MoS2是n型掺杂的，使得其发光效率仍然很低。在本文中，采用匀胶机旋涂的方法将共振吸收峰在514 nm附近的纳米金颗粒尽可能均匀的铺在单层、双层以及多层的MoS2样品表面，发现单层和双层样品的光致发光谱(PL谱)分别增强了约30倍和2倍同时伴随着峰位的蓝移，而多层样品的发光强度也略有增强。拉曼特性揭示了纳米金颗粒对单层和双层MoS2样品产生了明显的p型掺杂，从而增强了发光；同时纳米金颗粒的表面等离子激元效应对激发光的天线作用也是增强MoS2的光致发光的一个因素。
Abstract:
Molybdenum disulphide (MoS2), a layered quasi-two dimensional (2D) chalcogenide material, is a subject of intense research because of its electronic, optical, mechanical and physicochemical properties. Since the monolayer MoS2 is a direct-gap seminconductor, it is widely used in the field of light-emitting area. However, its photoluminescence (PL) efficiency is very low due to excessive doping in monolayer MoS2 and rich non-radiative centers. In this letter, we reportits synthesis using the gold nanoparticles which have a resonance absorption peak around 514 nm. The gold nanoparticles are dispersed on the surface of the MoS2 samples by means of spin-coating. Then, we measure the photoluminescence (PL) of the monolayer, bilayer and multilayer samples before and after the spin-coating, and find a great enhancement in the PL intensity of the monolayer sample. Also, the PL intensities of bi-layer and multiple layer MoS2 samples are slightly enhanced. Our work shows that gold nanoparticles may impose an obvious p-doping effect to the monolayer and bi-layer MoS2 samples to enhance the PL, and a surface plasmon polariton effect of the gold nanoparticles is also a positive factor for the enhancement.
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