Thermally tuning of the photonic band gap of SiO2 colloid-crystal infilled with ferroelectric BaTiO3

Abstract

${\mathrm{SiO}}_2$ colloid crystal infilled with ${\mathrm{BaTiO}}_3$ was synthesized by a process of self-assembly in combination of a sol–gel technique. It is found that infilling of the fully crystallized ${\mathrm{BaTiO}}_3$ into the colloid assembly can enhance the photonic band gap significantly. In the vicinity of the ferroelectric phase transition point of ${\mathrm{BaTiO}}_3$ (100–150 °C), the photonic band gap of the assembly exhibits a strong temperature dependence. At the Curie point, the band gap has a 20 nm redshift, and the optical transmittance reaches its minimum. Such a temperature-tuning effect in the photonic band gap should be of high interest in device applications.