Dielectric properties and photoluminescence of diatomaceous silicas

Abstract

Silica shells produced by diatoms have been studied to investigate their potential for applications in electronic and photonic devices due to their dielectric and photoluminescent properties. Dielectric measurements for low (1k-1MHz) and high (∼1GHz) frequencies were performed on processed diatomaceous earth samples and compared with measurements for artificial porous silica samples. Photoluminescence spectra for a sample of freshwater benthic diatoms were obtained and compared with silica spectra. The ratio of the 3.2eV photoluminescence peak compared to a peak at ∼2.20eV is smaller than for pure fused silica, and there is evidence of extra shoulder peak near 2.2eV for diatogenic silica. © 2005 Australian Institute of Physics.