Optical properties of Te doped GaP single crystals

The optical properties of Te doped GaP single crystals were investigated in the spectral range of 0.20–3.0 μm. It was found that the spectral distributions of R, n, ϵr and σr reflect sharp structure due to valence to conductiondashband transitions (Eg, E0, E1 and E2) having the energies 2.16, 2.75, 3.65 and 5.39 eV, respectively. It was found that the Te doped GaP single crystals exhibit indirect allowed optical transition associated with three phonons of energies 0.047, 0.038 and 0.050 eV. Two scattering mechanisms were detected in GaP:Te crystals, the first one is operating in the wavelength region 0.8–1.3 μm and is due to acoustical vibration, while the second one is operating in the wavelength region 1.3–2.85 μm and is due to impurity (Te) ions.