Electronic structures and optical properties of [formula omitted] by first-principle calculations

Abstract

First-principle calculations on the electronic structures and magnetic properties of Na doped in CuInSe 2 with different percentages reveal that the parameters and band gap increase with increasing Na. It reveals that the band gap increases 0.114 eV for 1/8 Cu replaced by Na, which exists in good agreement with the former calculation. We also discuss the differences of the complex dielectric function and the absorption spectrum of Cu 1− x Na x InSe 2. We find that the peak of the imaginary part of dielectric function occurs at about 1.5 eV introduces the inter-band transition of Cu-3d and Se-4p states. From the absorption spectrum, we can see that a distinct peak appears at about 2.85 eV with x = 0.083 and 0.0625 and a smooth increase without a peak appears for the other content of Na. Our result gets the right best equilibrium when x = 0.0833 and is in good agreement with experiments.