en مواد اپتیکی و فرامواد Optical Materials and Metamaterials پژوهشي Research <me<illegal tag>ta charset="UTF-8" >In the density functional theory (DFT), optical properties of Sc₂C(OH)₂monolayer are studied with and without silicon impurity. In the presence of silicon impurity, the structure and properties of this compound were changed from a semiconductor with a 0.57 eV band-gap to a topological insulator with a zero band-gap and a band inversion. With and without the silicon impurity, the spectral features in this compound originate from the electron transition from the p-Si and p-C to d-Sc and s-H, respectively. The values of optical constants are increased in the doped-structure with respect to the pure structure. Density functional theory (DFT), Electronic properties, MXenes, Optical properties, Sc2C(OH)2 monolayer, Silicon impurity. 99 106 http://ijop.ir/browse.php?a_code=A-10-901-1&slc_lang=en&sid=1 Reihan Nejatipour nejati.r@lu.ac.ir 10031947532846004462 10031947532846004462 Yes Department of Physics, Lorestan University, Khoramabad, Lorestan, Iran Mehrdad Dadsetani dadsetani.m@lu.ac.ir 10031947532846004463 10031947532846004463 No Department of Physics, Lorestan University, Khoramabad, Lorestan, Iran