Effects of form and surface on optical properties of porous silicon

Abstract

An effective medium approximation which includes surface contributions has been used to model the optical properties of porous silicon (p-Si) [1] as a bundle of parallel c-Si wires covered by different materials. It was previously shown that such an approach may be in the right direction when compared with some experimental measurements, but for example the effective absorption coefficient fit was out of range. Since the original model did not consider overlapping or interconnectivity between the wires, in this work, an interpolation formula [2] to study the role of the interconnectivity and the morphology on the optical properties is used. The new model is used to fit the absorption coefficient results on a sample of p-Si made with the standard technique.