Study of the effect of dopant on oxide thin films for optoelectronic applications

Abstract

In this work, we chose to deposit dopant cobalt oxide with manganese, lanthanum, tin and zinc by spray pneumatic method. The Co3O4:N (N= Mn, La, Sn and Zn) thin films were deposited on heated glasses substrates (TS = 400°C) using a homemade pneumatic spray method (PSM). The solution concentration and deposition time are 0.1 M and 4min respectively. The effect of N doping concentration on structural, optical and electrical properties of cobalt oxide were investigated. The elaborated films were characterized by X-ray diffraction, UV-Vis spectroscopy, atomic force microscopy (AFM) the three-dimensional (3D), energy dispersive spectroscopy (EDS), and four points probe measurements. The XRD study showed that all films were polycrystalline consisting with spinel cubic phase orientated along to (111) plane. The lattice strain and crystallite size were estimated by Williamson-Hall method. The morphology of N-doped Co3O4 thin films shows a homogeneous surface with straight acicular nanorods (SANRs). EDS analysis showed the presence of peaks associated with Co, O and N elements which confirm the composition of the thin films. The optical band gaps vary from 1,42 to 1,49 eV of Egop1 and Egop2 varies from 1,730 to 2,118 eV. In addition, the electrical measurement shows a maximum electrical conductivity (σM = 15,536 (Ω.cm)-1) at 6% wt of Mn, (σL = 22,858 (Ω.cm)-1) at 10 wt% of La, (σS = 16,875 (Ω.cm)-1) at 8% wt of Sn and (σZ = 24,266 (Ω.cm)-1) at 6% wt of Zn.