SPECTRAL ELLIPSOMETRY INVESTIGATION OF ZN0.53CD0.47SE LATTICE-MATCHEDTO INP

Spectral ellipsometry at 300 K, in the range 0.8-5.5 eV, has been used to study the bulk and surface oxide properties of a molecular-beam-ep itaxy grown Zn0.53Cd0.47Se/InP film (approximate to 1 mu m thick). We have observed the direct gap E-0, which exhibits a well-defined excito nic structure, its spin-orbit split component E-0+Delta(0), as well as the spin-orbit split E-1, E-1+Delta(1) doublet. The experimental data over the entire measured spectral range (after oxide removal) have be en fit using a model dielectric function based on the electronic energ y-band structure near critical points plus excitonic and Coulomb enhan cement effects. The influence of a native oxide on the optical propert ies also was investigated.