Spectroscopic ellipsometry studies of HgI2 surface roughness effects and optical properties of [KHgI3, H2O]

Below the energy-band absorption edge (∼2.2 eV), the ordinary and extraordinary refractive indices of the film formed on a HgI2 substrate after 30 h exposure to air were found to follow the first-order Cauchy dispersion relationship nof=1.401+0.052/λ2 and nef=1.575+0.043/λ2 in the spectral range from 300 to 800 nm. The characteristics of the complex [KHgI3, H2O] formed on the HgI2 surface after potassium iodide (KI) etching have been investigated by taking into account the surface roughness.