The structural, electronic and optical properties of pure Cadmium sulfide (CdS) and its alloy Cd_x-1A_xS(A = Co, Fe and Ni) compounds were investigated using first principle based on density functional theory. Electronic band structure and optical parameters calculations were performed using two different methods; generalized gradient approximation in Perdew-Burke-Ernzerhof (PBE) as well as modified Becke-Johnson (mBJ) for the exchange-correlation potential. Lattice constant, volume and bulk modulus were evaluated for structural properties. The results of band structure, effective mass, density of states and magnetic moment were determined for electronic properties. Optical parameters including absorption coefficient, refractive index, optical conductivity and optical reflectivity have been computed from the dielectric function at energy range of 0 to 15 eV using the Kramers-Kronig transformations. Our results reveal that the present of dopant in pure CdS enhanced the absorption capacity at low energy regions with the absorption coefficient of Cd_0.75Fe_0.25 > Cd_0.75Co_0.25S > Cd_0.75Ni_0.25S > Pure CdS for the GGA-PBE method and Cd_0.75Fe_0.25 > Cd_0.75Ni_0.25S > Cd_0.75Co_0.25S > Pure CdS for the mBJ method. The ability of Cd_0.75Fe_0.25 and Cd_0.75Ni_0.25S to absorb at extensive range of electromagnetic radiation makes them potential materials for application in nano-optoelectronic industry. All the results were compared with available theoretical calculations and the experimental data.

纯硫化镉（CdS）及其合金Cd _x-1 A _x的结构，电子和光学性质基于密度泛函理论，使用第一原理研究了S（A = Co，Fe和Ni）化合物。电子带结构和光学参数的计算使用两种不同的方法进行；Perdew-Burke-Ernzerhof（PBE）以及改进的Becke-Johnson（mBJ）中的广义梯度近似具有交换相关性。评价晶格常数，体积和体积模量的结构性能。确定了带结构，有效质量，状态密度和磁矩的结果，以求电子性质。使用Kramers-Kronig变换从0至15 eV能量范围内的介电函数计算了包括吸收系数，折射率，光导率和光反射率在内的光学参数。对于GGA-PBE方法，_0.75 Fe _0.25 > Cd _0.75 Co _0.25 S> Cd _0.75 Ni _0.25 S>纯CdS，对于mBJ方法，Cd _0.75 Fe _0.25 > Cd _0.75 Ni _0.25 S> Cd _0.75 Co _0.25 S>纯CdS。Cd _0.75 Fe _0.25和Cd _0.75 Ni _0.25 S在广泛的电磁辐射下吸收的能力使其成为在纳米光电子工业中应用的潜在材料。将所有结果与可用的理论计算和实验数据进行比较。