The dielectric function of AlSb from 1.4 to 5.8 eV determined by spectroscopic ellipsometry

We have prepared AlSb substrates for optical measurements by chemomechanical polishing and etching. The quality of the surface was investigated with optical and electron microscopy and by Raman scattering and ellipsometry. We have measured the pseudodielectric function 〈ε〉(ω) of AlSb in the 1.4–5.8 eV photon-energy region with a spectroscopic ellipsometer. A peak value of 〈ε2〉=24.6 at 4 eV was reached. We list the refractive index, the reflectivity, and the absorption coefficient, and obtain the critical point parameters at 300 K. Finally, we fit the index of refraction of AlSb at low photon energies with a semiempirical model.