单分散性sio_2胶体微球自组装光子晶体的实验研究

Microstructure and optical property of colloidal photonic crystals based on self-assembly of monodispersed sio_2 microspheres

光子晶体是一种周期性电介质材料,具有光子带隙和光子局域等一系列优异的光学特性。制备了多种不同直径的单分散二氧化硅胶体微球,采用垂直沉积法将不同直径,以及同一直径不同浓度的二氧化硅胶体微球自组装成多种光子晶体薄膜,并用扫描电子显微镜和紫外—可见—近红外分光光度计对其微观结构和光学特性进行了表征,结果表明所得晶体薄膜具有三维有序结构,其表面存点、线缺陷。自组装得到的光子晶体薄膜存在明显的光子带隙特征,带隙位置与二氧化硅胶体微球直径有关,带隙中心波长与理论值一致。随着二氧化硅胶体微球浓度的增加,光子带隙深度增加,特性更好,但是,当浓度大于10%时,光子带隙的深度反而减小。

Photonic crystal is one kind of periodic dielectric materials,with a series of excellent optical properties such as photonic band gap and photon localization.Prepared a variety of different diameter monodisperse colloidal silica microspheres,than use different diameter,different concentrations of silica gel microspheres self-assembled into a variety of photonic crystal films through the vertical deposition method,and their microstructure and optical properties are characterized by scanning electron microscopy（SEM） and UV-visible-near-infrared spectrophotometer.The results show that the films proceeds with three-dimensionally ordered crystal structure,there are obvious point and line defects on its surface.Self-assembly photonic crystal films have significant features of photonic band gap,the gap＇s position is relevant to colloidal silica microspheres in diameter,and the band-gap＇s centeral wavelength consistent with the theoretical value,the depth of photonic band gap increase as increasing concentration of colloidal silica microspheres,which mean better photonic band gap properties,but when the concentration is more than 10%,the depth of photonic band gap will be reduced conversly.