Surface effects of the Hgl(2) crystal characterized by spectroscopic ellipsometry

We report on determination of the surface effects of mercuric iodide (HgI2) uniaxial HgI2 optical parameters with a fixed-polarizer, rotating-polarize r, and fixed-analyzer spectroscopic ellipsometer (PRPSE) after chemical pol ishing. The characteristics of the chemical complex [KHgI3,H2O] that forms on the HgI2 surface during KI etching have been investigated over the spect ral range from 400 to 800 nm. Surface roughness and effects of the ellipsom etric parameters of HgI2 were treated, and the thickness of the layer forme d on the surface was determined and analyzed by PRPSE. The surface roughnes s was modeled with the Bruggeman effective medium approximation. (C) 2001 O ptical Society of America.