Study of the optical properties of the nickel deposited one-dimensional porous silicon photonic crystal

Thin nickel layer was deposited onto the porous silicon photonic crystal surface and then thermally treated at 900°C. The optical analysis reveals that the shape of the photonic band gap is determined principally by the roughness of the high porosity layer. Nickel presence leads to the suppression of the photonic band gap and it is partially recovered after thermal treatment. The structural characterization shows that after thermal treatment the high porosity layer expands while the low porosity layer contracts, whereas in the upper region of the photonic device, nickel is diffused into the first H and L layers and reacts with silicon to form Ni₃Si and Ni₃₁Si₁₂ porous phases. The average size of them is about 24 and 30 nm depending on the nickel silicide phase.