Surface, interfaces, thin films

Optical properties and critical points of PbSe nanostructured thin films

M. G. Huseynaliyev^a, S. N. Yasinova^a, J. N. Jalilli^b, S. I. Mekhtieva<sup>b

a</sup> Institute of Natural Resources, Nakhchivan Branch, Azerbaijan National Academy of Sciences, Az-7000, Nakhchivan, Azerbaijan
^b Institute of Physics Azerbaijan Academy of Sciences, Baku, Azerbaijan

Abstract: The spectroscopic ellipsometry method is used to investigate the optical properties of PbSe nanostructured thin films formed by the chemical deposition method. Function $d^{2}\varepsilon/d \omega^{2}$ formed by numerical differentiation of experimental data of the dielectric function $\varepsilon/\omega$ is used for better structural resolution of the interband transitions and the determination of critical points. Theoretical fitting is performed using the “Graphical Analysis” program. The best fit is found for the two-dimensional (2D) shape of the critical point $(m = 0)$ for the energy region $E$ = 2–3 eV, and one critical point corresponding to $E_g$ = 2.5 eV is determined. This value is attributed to the $L_4\to L_6$ transition of the Brillouin zone.

Keywords: spectroscopic ellipsometry, Brillouin zone, chemical bath deposition, lead selenide, dielectric function, fitting, second derivative.

Received: 03.02.2020
Revised: 13.02.2020
Accepted: 13.02.2020

DOI: 10.21883/FTP.2020.06.49379.9362

 English version: Semiconductors, 2020, 54:6, 630–633

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