Optical constants and dispersion energy parameters of gallium phosphide

Abstract

UV-Vis-NIR spectrophotometer was used to study the optical constants and dispersion energy parameters of gallium phosphide (GaP) single crystal wafer grown by liquid- encapsulated Czochralski. The optical band gap of GaP was determined using band to band transition theory and was found to be 2.32 eV. The refractive index was evaluated from reflectance spectra and its value lies in the range 1.3 to 2.1 corresponding to the photon energy 1.5 to 5 eV. The dispersion energy and oscillator energy values of the GaP were determined using single oscillator model and their values are found to be 14.26 eV and 3.61 eV, respectively. The relation between optical band gap and oscillator energy was found to be Eo≈ 1.55xEg. Further, real and imaginary dielectric constants were plotted and the peak shows the photo transition process with electromagnetic interaction inside material.