| 초록 |
Novel photoluminescent Bragg-reflective porous silicon (PBR PS) exhibiting dual optical properties, both optical reflectivity and photoluminescence, were developed and used as explosive sensor. PBR PS samples were prepared by an electrochemical etch of n-type silicon under the illumination with a 300 W tungsten filament bulb. The etching solution consisted of a 1:1 volume mixture of aqueous 48% hydrofluoric acid and absolute ethanol. PBR PS exhibits strong red color reflection at 650 nm and strong red photoluminescence at 650 nm. The monolayer PS showed a broad PL spectrum with a full width at half maximum (FWHM) of 125 nm, however, PBR PS exhibited sharp PL peak which reached FWHM of 20 nm. Analysis on the changes of reflectivity and quenching PL indicated that the larger change in quenching PL of PBR PS compare to that of the monolayer PS, is due to the decrease in enhancement effect of luminescence. Amplified Bragg luminescence of porous silicon is ultra-sensitive to the explosive vapors whose vapor pressures are extremely low. |
