Electronic and optical properties of ZnSe by theoretical simulation TB-mBJ (Tran-Blaha modified Becke Johnson) associated to analysis techniques XPS (X-Ray Photoelectron Spectroscopy); REELS (Reflective Electron Energy Loss Spectroscopy) and PLS (Photoluminescence Spectroscopy)

摘要

Our work aims to establish a correspondence between the obtained theoretical and experimental results on the electronic and optical properties of ZnSe. The calculated DOS (Density of States) using the FP-LAPW method with the Tran-Blaha modified BeckeJohnson exchange-correlation potential reveal that the upper valence energy levels involve an important contribution from the Se-(4p and 3d) electron states with a small contribution from the Zn-2s states. The real (e1(w)) and imaginary (e2(w)) parts of the dielectric function show the anisotropy character of wZnSe. The main peaks appearing in the e2(w) spectrum, are calculated by summing over all contributions of electronic transitions between the pairs of bands Vn - Cn ' , where Vn is an occupied valence band and Cn ' is an unoccupied conduction band. Experimentally, the XPS (X-Ray Photoelectron Spectroscopy) analysis technique is used to show the clean and homogeneous state of ZnSe. To confirm the calculated electron transitions, we use the REELS (Reflected Electron Energy Loss Spectroscopy) technique of great sensitivity for displaying the electron interband transitions. The electron states in the w-ZnSe gap are determined through the Gaussian deconvolution of the photoluminescence spectrum (PLS).