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针对二氧化钒(VO2)薄膜在可调谐太赫兹功能器件中的应用,利用低温磁控溅射技术,在太赫兹和光学频段透明的BK7玻璃上制备出高质量的VO2薄膜.晶体结构和微观形貌分析显示薄膜为单相VO2单斜金红石结构,具有明显的(011)晶面择优取向,结构致密,表面平整.利用四探针技术和太赫兹时域光谱系统分析了薄膜的绝缘体-金属相变特性,发现相变过程中薄膜电阻率变化达到4个数量级,同时对太赫兹透射强度具有强烈的调制作用,调制深度高达89%.通过电学相变和太赫兹光学相变特性的对比研究,证实薄膜的电阻率突变主要与逾渗通路的形成有关,而太赫兹幅度的调制则来源于薄膜中载流子浓度的变化.该薄膜制备简单,成膜质量高,太赫兹调制性能优异,可应用于太赫兹开关和调制器等集成式太赫兹功能器件.
Aiming at the application of vanadium dioxide (VO2) thin film in tunable terahertz functional devices, a high quality VO2 thin film is prepared on the transparent BK7 glass in terahertz and optical frequency band by using low temperature magnetron sputtering technique. Morphology analysis shows that the film is a monoclinic VO2 monoclinic rutile structure with a preferential orientation of (011) crystal plane, compact structure and smooth surface. The dielectric properties of the thin film insulator (metal - insulator) are analyzed by four-probe technique and terahertz time-domain spectroscopy Phase transition and found that the change of the resistivity of the thin film during the phase change reaches four orders of magnitude and the terahertz transmission intensity has a strong modulating effect with a modulation depth of up to 89%. By comparing the phase transition of the electron with the terahertz optical phase transition , It is confirmed that the resistivity of film is mainly related to the formation of percolation pathway and the modulation of terahertz amplitude is derived from the change of carrier concentration in the film.The film has the advantages of simple preparation, high film quality, excellent terahertz modulation performance, Can be applied to integrated terahertz functional devices such as terahertz switches and modulators.