大面积金纳米线光栅的制备

利用激光干涉光刻和金纳米颗粒胶体溶液制备了宽度在100 nm以下且总面积达到平方厘米量级的金纳米线光栅结构.制备过程中,首先在表面镀有厚度约为200 nm的铟锡氧化物薄膜的面积为1 cm×1 cm的玻璃基片表面旋涂光刻胶,然后利用紫外激光干涉光刻制备光刻胶纳米光栅结构.有效控制干涉光刻过程中的曝光量、显影时间,获得小占空比的光刻胶光栅.再以光刻胶纳米光栅作为模板,旋涂金纳米颗粒胶体溶液.充分利用金纳米颗粒胶体溶液在光刻胶表面浸润性差的特点,限制旋涂后留存在光刻胶光栅槽中金纳米颗粒的数量,从而达到限制金纳米线宽度的目的.最后在250℃将样品进行退火处理5 min.获得了周期为400 nm且占空比小于1:4的金纳米线光栅结构,其有效面积为1 cm².以波导共振模式与粒子等离子共振模式间耦合作用为特征的光谱学响应特性验证了波导耦合金属光子晶体的成功制备,为小传感体积新型生物传感器的开发提供了性能良好的金属光子晶体芯片.

Fabrication of Large-area Gold Nanowires Grating

Grating structures of gold nanowires with a width of sub-100 nm and a total area in the order of square centimeters are prepared using interference lithography and colloidal gold nanoparticles.In the fabrication, photoresist is firstly spin-coated onto the glass substrate that is coated with a layer of indium tin oxide as thick as 200 nm.Grating structures are then produced by interference lithography into the photoresist.Through controlling the exposure dose and the development time, small duty cycles are achieved with the photoresist gratings.Thereafter, colloidal gold nanoparticles are spin-coated onto the photoresist master grating.Making use of the dewetting properties of the colloidal solution on the photoresist surface, very limited amount of gold nanoparticles remain on the photoresist grating and are confined into the grating grooves.In combination with the small duty cycle of the photoresist grating structures, this mechanism enables realization of narrow gold nanowires.In the final stage of the fabrication, the sample is heated to 250℃ for about 5 minutes.Gold-nanowire gratings with a duty cycle of 1:4 and a period of 400 nm are achieved, which have an effective area of 1 cm².The optical response featured with strong coupling between the waveguide resonance mode and particle plasmon resonance confirms the successful fabrication of the waveguided metallic photonic crystals.This device may be utilized as the central part of the biosensors with small sensing volumes.