About complex refractive index of black Si

Emil Pincik – Robert Brunner – Hikaru Kobayashi – Milan Mikula

   The paper deals with the complex refractive index in the NIR-VIS light region of two types of samples (i) - as prepared black silicon and (ii) - thermally oxidized black silicon (BSi) nano-crystalline specimens produced both by the surface structure chemical transfer method using catalytic Ag evaporated spots (as prepared sample) and by the catalytic Pt catalytic mesh (thermally oxidized sample). We present, compare, and discuss the values of the NIR-VIS complex refractive index obtained by calculation using the Kramers-Krönig transformation. Results indicate that small differences between optical properties of as prepared black Si and thermally oxidized BSi are given by (i) - oxidation procedure, (ii) - thickness of the formed black Si layer, mainly, not by utilization of different catalytic metals, and by iii) the different thickness. Contamination of the surface by different catalytic metals contributes almost equally to the calculated values of the corresponding complex refractive index.

Keywords: black silicon; porous silicon, complex refractive index, catalytic mesh

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