Precisely tuned emission from porous silicon vertical optical cavity in the visible region

Publisher Website
Google Scholar
Abstract
The operating peak energy of a porous silicon (PS) cavity can be completely controlled over a wide range of 1.5–2.2 eV, using a PS‐based Fabry–Perot resonator composed of a light‐emitting active PS layer and two high‐reflectivity mirrors. When the PS devices are excited by a uv laser, quite narrow spectra (10–40 meV in full width at half‐maximum) are observed without any significant signs of side mode. The central photon energy is precisely and continuously tuned simply by changing the anodization parameters. The key issues of the controlled device operation are adjustment of the optical thickness of the active PS layer to an appropriate value and fabrication of the quarter‐wavelength multilayered PS mirror with a high reflectivity. The spectral qualities of the emitted light are also discussed by theoretical analyses on the basis of a simplified model. These results suggest that the PS devices operate as sharp band‐pass optical filter and the PS materials are available for novel silicon‐based microphotonics.