COMPUTATIONAL AND EXPERIMENTAL STUDY OF ELECTRONIC STRUCTURE AND OPTICAL PROPERTIES OF NEODYMIUM DOPED ARSENID SULFID CRYSTAL

In this work, we have performed electronic structure and optical investigations for pure and neodymium-doped As2S3 compound using both the experimental and first-principles calculation approaches. Photoluminescence studies were carried out in the infrared (600-1350 nm) region at room temperature. It was found that the observed maxima in the PL spectrum for pure compound are due to donor-acceptor recombination and transitions from the Fermi level to the valence band. Photoluminescence of neodymium-doped As2S3 crystal was studied by us for the first time. Due to the transfer of photon energy, a sharp increase in intensity was observed in the intraatomic transition of neodymium F-4(3/2) - I-4(11). The electronic and optical properties were studied by density functional theory (DFT). The origin of the energy bands was clarified by density of state and the nature of the fundamental absorption edge was analyzed it was established that the crystal has a band gap of indirect type with Eg=2.18 eV for GGA -SG15 (1.65 eV FHI-GGA, 182 eV HGH-GGA). The dielectric function (real part epsilon 1(omega) and imaginary part epsilon 2(omega)) and absorption coefficient alpha(omega) were calculated for pure and Nd-doped As2S3 and compared with experimental data. The calculated absorption spectrum imply that Nd doping causes a red-shift of absorption peaks. The results of this work allow us to say the possibility of using this compound as optical amplification and lasing.