Some optical and electrical properties of the As2Se3−xTex system

Some optical and electrical properties of the As₂Se_3?xTe_x system (0 ≤ x ≤ 0.15) have been studied. The value of the optical gap decreases from 1.74 eV to 1.59 eV. The slope of the absorption edge changes, so that value of E_o from the relation α ～ exp ($\text{h}\text{?}\text{ω}\text{E}{}_{\mathrm{o}}$) exhibits a maximum value in neighbourhood of composition As₂Se_2.9Te_0.1. The d.c. and a.c. conductivities have been studied. The value of the activation energy E_el ～ 1.8 eV is almost unchanged up to x = 0.15. The a.c. conductivity fulfils the relation $\text{б(ω) ～ ω}{}^{\mathrm{<mtext>s</mtext>}}$ where s ? 1 and 1.1. at frequencies f < 1 kHz and f > 1 kHz respectively.