Analysis of electronic and optical properties of copper iodide (γ-CuI) by TB - mBJ method - A promising optoelectronic material

Density functional theory (DFT) calculations using full potential linearized augmented plane wave (FP-LAPW) method as implemented in the Wien2k code have been performed to investigate the structural, electronic and optical properties of copper iodide (gamma-CuI) in zinc blende phase. Optical properties have been studied theoretically and various optical constants such as complex dielectric constant, refractive index, reflectance, transmittance, absorption co-efficient, optical conductivity and electron energy loss are discussed with respect to the photon energy. We have also discussed the progresses of the overall results of Tran-Blaha modified Becke-Johnson (TB-mBJ) potential and have been compared to the standard generalized gradient approximation (GGA) method. Exciton binding energy is also calculated and the value is found to be 60 meV. As the absorption coefficient is maximum in the ultra-violet (UV) region for CuI, it is a very good material active in UV region and hence it can be used in optoelectronic device applications.