Opto-electronic properties of HfO2: A first principle-based spin-polarized calculations

Wide band gap and highly dielectric, HfO2 compound has been investigated for two different phases viz. cubic and monoclinic using density functional theory (DFT) calculations to study structural and optoelectronic properties. For the calculations, PBE-GGA and Tb-mBJ exchange correlations have been used. Volume optimization curve confirmed that the monoclinic phase is most stable as compared to the cubic one, which is consistent with its experimental outcome. Both density of states (DOS) and band structure profile represent the wide band gap for the HfO2 compound, having the gap in the range of 5.4-5.8 eV for the cubic and monoclinic phase of HfO2 compound under the TB-mBJ potential. The observed bandgap matches greatly with its experimental and other theoretical investigations on HfO2 compound. In addition,we investigated the different optical parameters such as dielectric function, refractive index, extinction coefficient, absorption coefficient, optical conductivity, reflectivity and electron energy loss in detail for the HfO2 compound. The maximum value of the dielectric constant found to be similar to 2.89 at zero frequency. Estimated refractive index found to be similar to 1.7, which validates the standard Penn Model. Our calculations show a high static dielectric constant for the HfO2 compound. Absorption found to be maximum in UV region of em radiation, which is suitable for its application in UV based devices. It is noted that the estimated optical parameters, along with electronic properties, are in good agreement with experimental and theoretical studies.