Optical properties of Zn-doped InP single crystals

The optical properties of Zn-doped InP single crystals were investigated and compared with those of InP crystals in the spectral range of 0.20–3.0 μm. It was found that the positions of the critical points (CP) in the Brillouin zone (BZ) at shorter wavelengths (E′0, E1, E0 + Δ0) were insensitive to Zn impurities; the intensity of these peaks and the refractive index at longer wavelengths increased. Also, the shape of the absorption coefficient, the absorption index change and the energy gap as well as the natural frequency decreased. Teo linear empirical expressions relating the refractive index difference between InP:Zn and InP in the energy range below and above the energy gap of InP:Zn have been proposed. Single scattering mechanism was detected in InP:Zn in the spectral range 1.12–2.24 μm, refered to as acoustical vibrations.