后退火处理对铟锡氧化物表面等离激元共振特性的影响

近年来，表面等离激元光子学发展迅速，并取得了众多新成果.重掺杂半导体材料的表面等离激元共振性质的研究，也得到了人们越来越多的关注.本文通过纳米球刻印技术制备准三维二氧化硅纳米球阵列，在阵列上沉积铟锡氧化物薄膜，通过不同条件下的后退火处理改变铟锡氧化物薄膜的载流子浓度和载流子迁移率，并研究随着材料性质的改变其相应表面等离激元共振特性的变化规律.结果表明：退火处理均使铟锡氧化物薄膜的晶粒长大，光学透过率增加；在空气中退火会导致铟锡氧化物薄膜的载流子浓度减少，其表面等离激元共振峰红移；而真空退火则使铟锡氧化物薄膜的载流子浓度增加，共振峰蓝移.这些研究结果可为后续铟锡氧化物表面等离激元材料及器件的研究提供科学依据和实际指导.

Effect of annealing treatment on characteristics of surface plasmon resonance for indium tin oxide

With the development of modern micro-processing technology, the basic theory and relevant applications for surface plasmon have formed a new research direction which is known as surface plasmon photonics. The traditional plasmonic materials are noble metals, such as gold and silver, but they have some limitations that may hinder their application in plasmonic devices, such as lack of the chemical stability in air, difficulty in modulating by external field, large optical losses in the infrared wavelength range, etc. It has been demonstrated that transparent conducting oxides are a good candidate of plasmonic materials working in the infrared frequency range because of their low optical loss and tenability. Here in this work, the quasi-three dimensional silica nano-sphere array is prepared by nano-imprint lithography. Indium tin oxide (ITO) film is deposited on the array. The transmission properties are measured and the excitation modes of surface plasmons are analyzed for the samples obtained. Then, we focus on the effect of annealing treatment on characteristics of surface plasmon resonance for ITO thin films. The carrier concentration and carrier mobility of the ITO thin films annealed under different conditions are changed, and the corresponding surface plasmon resonance characteristics are investigated. The main results obtained in this work are as follows. 1) Mono-disperse SiO₂ spheres, quasi-ordered monolayer SiO₂ mask and ITO films with high transmittance (≥ 85%) and high electrical conductivity are obtained. Experimental results show that a surface plasma resonance at a wavelength of 1780 nm is excited for the glass/sphere/ITO system. 2) The grain size of ITO thin film after being annealed turns large, resulting in the increased optical transmittance of samples. 3) The carrier concentration of ITO film annealed in the air decreases, leading the resonance peak of surface plasmon to be red-shifted. 4) The carrier concentration of ITO thin film annealed in vacuum increases and the resonance peak is blue-shifted. These results obtained in this work contribute to the application of surface plasmon devices fabricated by ITO materials.