Document Type : Research
Author
Assistant prof, Department of Physics, Ro.C. Islamic Azad University, Roudehen, Iran
Abstract
A B S T R A C T
the optical properties of porous silicon with different porosity levels were systematically investigated. Samples with various porosity were fabricated, and their optical behavior in the visible wavelength range was analyzed with particular emphasis on the effective dielectric function, refractive index, and optical band gap. The real and imaginary parts of the effective dielectric function were calculated in order to evaluate the polarization response. The results indicate that increasing porosity leads to a noticeable decrease in the real part of the dielectric function, which can be attributed to the increased contribution of the air phase and the consequent reduction in the effective density and polarizability of the medium. At the same time, the imaginary part of the dielectric function exhibits a significant decrease with increasing porosity, revealing a substantial reduction in optical absorption and dielectric losses in highly porous structures. . The real part of the refractive index decreases systematically as porosity increases, confirming the dilution of the optical medium and the weakened light–matter interaction. Moreover, the imaginary part of the refractive index approaches very low values in the visible region for samples with higher porosity, indicating suppressed absorption and reduced optical attenuation. These results demonstrate the feasibility of tailoring the optical response of porous silicon through precise control of its porosity. Furthermore, the optical band gap of the samples increases from approximately 1.8 to 2.3 eV with increasing porosity. This band gap widening can be attributed to quantum confinement effects,
Keywords
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