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.

Effects of Deposition Time And PH on The Characterization of Chemically Synthesized Composite Nano-Wires of Cu2S Thin Films

“…The obtained energy gap values are approximately the same values obtained by (Ismail et al, 2020). ) l(nm) (Ghdeeb, 2015). While the absorption is 8.47 % for pH=11.4 and decreased to 1.6 % for pH =8.4 in the visible range.…”

“…This makes the films to be suitable for use as thin coatings on windows to control the amount of light that enters a building and also reflect as much infrared radiation as possible. While, from figure (8b), one can see that the transmission of the thin films decreases from 93.27% for a deposition time of 4 hours to 81.73% for deposition time of 10 hours and this is attributed due to the increase in the films' thickness (Ghdeeb, 2015). Increasing the thickness of (Cu2S) thin films leads to an increase in the depth of donor levels associated with these vacancies increases which cause these levels to be available for photons to be absorbed.…”

“…Cu2S is a well-known material because of its significant optical and electrical properties which allow copper sulphide to be utilized in different important applications (Ismail et al, 2020) such as optoelectronic devices (Kim et al, 2017), absorbers for solar energy conversion (Ghdeeb, 2015), ion batteries and superconductors (Li et al, 2017;Liu et al, 2018), gas sensors (Sagade & Sharma, 2008), heterojunction photodetectors such as Cu2S/CdS, ZnO/Cu2S, Cu2S/ZnS and Cu2S/n-Si (Guo et al, 2014;Ismail et al, 2019;Zhan et al, 2020), and supercapacitors (Bulakhe et al, 2016).…”