热退火诱导纳米银膜形貌变化对表面等离激元共振特性的影响

Effects of Morphology Evolution on Surface Plasmon Resonance of Nano-Ag Films Treated by Different Thermal Annealing Temperatures

采用磁控溅射技术制备并通过不同温度的快速热退火得到了不同表面形貌的纳米银膜。利用XRD,SEM和紫外-可见-近红外透射光谱等技术研究了纳米银膜的结构、表面形貌与光学性质。实验结果表明,随着退火温度的升高,银膜开口面积分数、银岛(纳米粒子)间距增大,长宽比减小,银岛由各向异性的蠕虫状变成各向同性的纳米球;表面等离激元共振带发生连续的蓝移,半高宽变窄。分析表明,纳米银膜的表面等离激元共振特性可以通过热退火诱导的表面形貌变化实现调整。

The nano-Ag films were prepared by RF magnetron sputtering technique,and all of them were treated by rapid thermal annealing at different temperatures.The structure,the morphology and the optical properties of the annealed nano-Ag films were characterized by X-ray diffraction,scanning electron microscopy,and UV-Vis-NIR spectroscopy.The experimental results show that the open area fraction of the film and spacing between islands or nanoparticles increase with the increase of the annealing temperature,while the aspect ratio decreases.The anisotropic worm-like island films have been reshaped into isotropic nanospheres.The surface plasmon（SP） resonance band blue shifts and narrows continuously with increasing heating temperature.Analyses show that the SP resonance of the nano-Ag films can be modulated by morphology evolution induced by rapid thermal annealing.