Investigating the Optical Properties of Cadmium Selenide under Nickel Doping

Siahkali, Zahra; Ghobadi, Nader; Mehrparvar, Dariush; Farrokhzadi, Mohammad

Investigating the Optical Properties of Cadmium Selenide under Nickel Doping

Document Type : Original Article

Authors

Zahra Siahkali ¹

Nader Ghobadi ²

Dariush mehrparvar ¹

Mohammad Farrokhzadi ³

¹ Department of Physics, Faculty of Science, Malayer University, Malayer, Iran

² Mlayer university

³ Department of Mathematics, Technical and Vocational University, Tehran, Iran

Abstract

The Ni doped CdSe nanostructured thin films during deposition procedure that govern altering of the optical transitions have been investigated. Concentration of Ni as doping inside CdSe from 0.03 mol in form of nanostructured thin layers have been fabricated through a simple chemical solution deposition approach. Doping of the Ni to CdSe add the new transitions in related to NiSe, means the tiny concentration of Ni ions create the new transition to CdSe that sample have multiple optical bandgap. Although absorption due to impurity can be considered as absorption inside band gap region below the fundamental (band-to-band) but absorption due to doping in nanostructured thin films aren’t as absorption inside band gap and their optical transitions are band to band so have broad lines and powerful in absorption spectra. There is an order in band gap changing with doping concentration raising so that increasing of the Ni2+ions decreases the optical band gap to 1.59eV although optical band gap for CdSe in bulk state is 1.74eV , so doping procedure decreases optical bandgap of CdSe that is mean doping procedure creates the new structure. It has shown that it’s possible to determine the Urbach energy of the samples from the absorption spectrum without the need to determine the adsorption coefficient from the determination of thickness.

Keywords

Ni doping

chemical solution deposition

Nanostructure thin film

Urbach energy