Experimental Study of Precursor Concentration the Co3O4 Thin Films Used as Solar Absorbers

Abstract

Received: 11 December 2019 Accepted: 6 February 2020 The objective of this work is to develop Co3O4 films and to investigate the influence of different precursor concentration on the structural, morphological, optical and electrical properties of Co3O4 thin films, in order to improve the optoelectronic properties of these films. Finally, we have developed thin films of Co3O4 at different precursor concentrations (0.05 to 0.15 mol/l) under a substrate temperature set to 400°C and 4 minutes as deposition time. XRD analysis has shown that the deposited layers have a cubic spinel structure with a preferential orientation along the direction (311). The morphological studies have shown that the surface morphology of the films was almost homogeneous and dense. The presence of the peaks associated with the Co and O elements, which were present in the EDS analysis, confirmed the composition of the films. The optical characterization of our film has shown a low transmittance (from 16 to 0.9%) in the visible region and the IR region varies between 40 to 2% over the range of precursor concentration varied between 0.05 and 0.125 mol/l and a high absorbance of the order of 100% for the film deposit of 0.15 mol/l. The obtained gap values are ranged from 1.44 to 1.52 eV and 2.05 to 2 eV for lower and higher energy regions in the range of precursor concentration 0.05–0.125 mol/l. The film prepared at 0.15 mol/l, had a good p-type electrical semiconductor and good absorbance of sunlight.