Vertical deposition and spectral characteristics of CdSe-SiO₂ photonic crystals

CdSe films were electrodeposited on indium tin-oxide coated glass (ITO-glass). Subsequently three dimensional (3D) SiO₂ colloidal crystals were prepared on the films through vertical deposition technique. As a result, the dielectric constant on the surface of the CdSe film could be tuned. SEM showed that colloidal microspheres of 500nm were closely packed into fcc arrangement on the film surface. The colloidal crystal was a mixture of small-size domains with the ordered scale at tens of micrometers. A wide photonic band gap was observed in the UV-vis-NIR spectrum of CdSe-SiO₂ photonic crystal, which was different from that of SiO₂ colloidal crystal prepared on ITO-glass. The stop band at near infrared shifted to short wavelength with the incidence angel decreasing. CdSe-SiO₂ photonic crystals prepared could be used as camouflage materials.