Dielectric function of epitaxial ZnSe films

Abstract

We examine various ZnSe spectra to obtain that which best represents the dielectric response ε of ZnSe. The measured evolution of pseudodielectric function 〈ε〉 data with chemical etching shows that the natural overlayer on ZnSe can be modeled accurately only if we assume that it contains amorphous Se. Hence previous assumptions made in correcting 〈ε〉 mathematically are not correct, and data obtained on stripped samples yield the best representation of ε.

Spectroscopic ellipsometric analysis of ZnSe1−xOx layers with different O compositions

“…Spectroscopic ellipsometry ͑SE͒ is a suitable tool to determine the dielectric function of semiconductors and in particular, to measure the spectral dependence of the dielectric function. 11,12 Several groups have studied the optical properties of ZnSe 1−x O x with different oxygen contents. It is an optical technique that requires an accurate model of the measurement process for data analysis.…”

Optical properties of Zn1−Mn Se (x≤0.78) epilayers

“…Before measurements, samples were etched in a 1:3 mixture of NH 4 OH (29%)/methanol to remove the natural oxide overlayer [11]. Although it was reported that such an etching process may roughen the sample surface [16], we will not make corrections for this, since neither the real microstructure nor the composition of the residual overlayer is known. The dielectric function e is obtained by reducing the ellipsometric data with the two-phase (ambient-ZnMnSe) model.…”