Investigation of structure, dielectrical, optical, and electronic properties for Y_(0.225)Sr_(0.775)CoO_3 thin films deposited on different single crystal substrates using pulsed laser deposition (PLD) method

摘要

The optical properties of these films were measured using UV/Vis spec-trophotometer. The optical parameters; energy gap (E_g), refractive index (n), extinction coefficient (k), the optical energy gap affected strongly by changing the substrate type. Moreover both of oscillating energy (E_o), dispersion energy (E_d), the effective mass of these films with different substrate had been calculated optically, another important parameters, such as the dielectric constant (ε~) and dielectric loss (ε~()) and both of the real part (σ_1) and imaginary part (σ_2) of optical conductivity were determined. The ratio of VEL to SEL as functions of photon energy for Y_(0.225)Sr_(0.775)CoO_3 films was calculated optically. Finally, the density of both valence band (N_V) and conduction band (N_C) for these films has been calculated. The dielectric constants for these films were determined.