Fabrication and optical characterization of a porous silicon distributed Bragg reflector

Abstract

This study examine the reflection band characteristics of a distributed Bragg reflector (DBR) porous silicon (PSi) and the effect of etching time on the formation of the Bragg photonic structure. A PSi DBR with the Bragg filter photonic structure was fabricated using a computer-generated square current density wave. The multilayered photonic crystals of the PSi DBR exhibited a specific wavelength reflection with high reflectivity in the optical spectrum. This reflective wavelength was controlled by adjusting the etching time and depending on the waveform, could be observed throughout the entire visible range. These results are important for the fabrication of specific reflectors and full-color filters. We further investigated the effect of the current density’s waveform on the formation of the PSi DBR. We found that as the etching time was increased, the reflection band of the PSi DBR shifted to longer wavelength by about 150 nm. The reflection band characteristics of 16 PSi DBR samples for various current densities were investigated in more detail. We established that the PSi DBR exhibited linear dependence of the reflection wavelength on the current density.