Reversible charging effects on optical properties of porous silicon

In our previous theoretical studies, through an effective medium approximation it was deduced that the effect of introducing charge is to decrease the absorption and coefficient of the material. In the present experimental studies porous silicon samples have been charged, depending on the current intensity, the intensity of the Photoluminescence Excitation response can be modulated in the energy range 1.5–2.6 eV. A decrease in the emission intensity with an increase in charging current has been observed. This effect is reversible and the recovery time is found to be in the range of 4–6 min. The variation of charging effect with the thickness of porous silicon layers has also been studied. An increase in the lowering of the intensity with an increase in thickness has been observed.