Characterization of stain-etched porous silicon

We have performed infrared absorption, continuous-wave photoluminescence, and nanosecond photoluminescence decay measurements to characterize stain-etched porous silicon. Stain-etched porous silicon samples were prepared by etching boron-doped crystalline silicon wafers in a solution of HF:${\mathrm{HNO}}_3$:${\mathrm{H}}_2$O with ratios of 1:5:10 by volume. The dependence of continuous-wave photoluminescence intensity upon temperature and excitation energy has been studied. We have also investigated the dependence of nanosecond photoluminescence decay upon temperature, excitation energy, and emission energy. Our results suggest that the photoluminescence in stain-etched porous silicon might be due to the presence of siloxene-type bonding configuration in an amorphous alloy of silicon, oxygen, and hydrogen.