Optical properties of ZnTe films prepared by molecular beam epitaxy

In this paper, the optical properties of ZnTe epitaxial thin films prepared by molecular beam epitaxy (MBE) onto GaAs single crystal substrates are studied using the combined optical method employing a simultaneous interpretation of experimental data obtained by means of variable angle spectroscopic ellipsometry (VASE) and near-normal spectroscopic rellectometry (NNSR). The spectral dependences of both the optical constants, i.e. the refractive index and extinction coefficient, characterizing these films are presented within the spectral region 230-850 nm. It is shown that the optical properties of the ZnTe epitaxial films depend on the values of their thickness. This conclusion was found using the model of the optical constants exhibiting a profile across these films. A roughness of the upper boundaries of the ZnTe films and the existence of a very thin native oxide layer (NOL) on these boundaries are taken into account within the optical analysis. (C) 2004 Published by Elsevier B.V.