Effect of Ag incorporation on structural and opto-electric properties of pyrolized CdO thin films

M R Alam,M Mozibur Rahman,M K R Khan,A M M Tanveer Karim

doi:10.1007/s40089-018-0251-5

Abstract

We have investigated the structure, morphology and opto-electric properties of CdO and Ag-incorporated CdO thin films prepared by chemical spray pyrolysis (CSP) method. The X-ray diffraction (GIXRD) study confirms that CdO samples are highly polycrystalline with cubic structure. The AFM study shows smooth surfaces both for CdO and Ag-CdO thin films. The direct band gap energy varies from 2.25 to 2.50 eV depending on Ag content in the films. Urbach energy reversal in optical band gap indicates that several localized states are present above Fermi level or near at the conduction band. The optical properties, such as refractive index, optical conductivity and nonlinear optical susceptibility, are found dependent on Ag content. A combined effect on the transport properties has been observed with the incorporation of Ag in CdO. The metal-like electric conduction of CdO film has been removed up to a temperature Tc for Ag doping. The n-type carrier concentration of CdO is reduced with increasing Ag content and the concentration is of the order of ~ 1020 cm−3.

Highlights

CdO is a familiar n-type semiconductor with band gap energy (2.2–2.7) eV [1,2,3]
The opto-electrical properties of undoped and doped CdO films depend on microstructure which can be controlled by changing the preparation conditions
CdO and Ag-incorporated CdO (Ag-CdO) thin films were prepared by chemical spray pyrolysis method on glass substrate at substrate temperature 350 °C and structural, optical and electrical properties were investigated

Summary

Introduction

CdO is a familiar n-type semiconductor with band gap energy (2.2–2.7) eV [1,2,3]. It is transparent to electromagnetic radiation in the visible to NIR spectral regions. Keywords Thin films · XRD · Band gap · Urbach tail · Activation energy The opto-electrical properties of undoped and doped CdO films depend on microstructure which can be controlled by changing the preparation conditions.

Results

Conclusion