The effect of thickness on the optical properties of Cu2S thin films

Abstract

In this work, the optical properties of Cu2S with different thickness(1400, 2400, 4400) Ǻ have been prepared by chemical spray pyrolysis method onto clean glass substrate heated at 283 oC ±2. The effectof thickness on the optical properties of Cu2S has been studied. Itwas found that the optical properties of the electronic transitions onfundamental absorption edge were direct allowed and the value of theoptical energy gap of Cu2S (Eg) for direct transition decreased from(2.4-2.1) eV with increasing of the thickness from (1400 - 4400)Ǻrespectively. Also it was found that the absorption coefficient isincreased with increasing of thicknesses. The optical constants suchas extinction coefficient, refractive index and the imaginary part ofthe dielectric constant have similar termed of variation for theabsorption coefficient.