Optical properties of Sulfur doped InP single crystals

Optical properties of InP:S single crystals were investigated using spectrophotometric measurements in the spectral range of 200–2500 nm. The absorption coefficient and refractive index were calculated. It was found that InP:S crystals exhibit allowed and forbidden direct transitions with energy gaps of 1.578 and 1.528 eV, respectively. Analysis of the refractive index in the normal dispersion region was discussed in terms of the single oscillator model. Some optical dispersion parameters namely: the dispersion energy (E d ), single oscillator energy (E o s ), high frequency dielectric constant ( ε ∞ ), and lattice dielectric constant ( ε L ) were determined. The volume and the surface energy loss functions (VELF & SELF) were estimated. Also, the real and imaginary parts of the complex conductivity were calculated.