Intraband light absorption in free-standing porous silicon

Abstract

We have prepared free-standing porous silicon (FPS) samples with various porosities using electrochemical etching. The result of a study combining absorption and photoluminescence (PL) from FPS samples with porosities in the range 53–76% is presented. A blue shift of the PL peak position and an increase of the PL intensity with enhancing porosity have been observed. Furthermore, the PL peak and intensity of porous silicon (PS) samples are compared with FPS samples. Our results show that the PL peak intensity reduces 1.5–2.5 times from PS to FPS. However, no notable shift of the PL peak position from PS to FPS has been observed.