The effect of deposition cycles on intrinsic and electrochemical properties of metallic cobalt sulfide by Simple chemical route. (October 2019)

• Record Type: Journal Article
• Authors: Ighodalo, Kester O.; Ezealigo, Blessing N.; Agbogu, A.; Nwanya, Assumpta C.; Obi, Daniel; Mammah, Sylvester L.; Botha, S.; Bucher, R.; Maaza, Malik; Ezema, Fabian I.
• Is Part Of: Materials science in semiconductor processing. Volume 101(2019)
• Page Start: 16
• Page End: 27
• Publication Date: 2019-10
• Subjects: Thin film CoS -- Williamson-Hall plots -- Intrinsic properties -- Nanostructures -- Electrochemical impedance spectroscopy (EIS); Semiconductors -- Periodicals; Integrated circuits -- Materials -- Periodicals; Semiconducteurs -- Périodiques; Circuits intégrés -- Matériaux -- Périodiques; Electronic journals; 621.38152
• DOI: 10.1016/j.mssp.2019.05.015
• Languages: English
• ISSNs: 1369-8001

Abstract

Abstract: In this paper, cobalt sulfide thin film was synthesized on glass and steel substrates via chemical route. The structure, surface morphology, and optical characterization of the deposited thin films indicated a strong relationship between the number of deposition cycles and intrinsic properties. The scanning electron microscope (SEM) showed a uniform morphology with randomly oriented nano-grains of cobalt sulfide film at varying deposition cycles. The XRD spectra revealed that the films became amorphous as the number of deposition cycles increased. The crystalline films had a hexagonal structure of average crystallite size of 27.55 nm. The optical transmission spectra of the films gave a direct band gap energy which varied between 1.90 eV and 2.20 eV with an average value of the optical conductivity was 1.77 10 17 S ̶ 1 . The electrochemical energy storage behavior of the electrodes was evaluated using cyclic voltammetery (CV), galvanostatic charge-discharge (GCD) technique and electrochemical impedance spectroscopy (EIS) in a neutral electrolyte of 0.1 M solution of Na2 SO4 performed on films deposited on a steel substrate. A specific capacity of 298.4 mAh/g at a scan rate of 20 mV/s was obtained at 30 deposition cycles. The SILAR deposited CoS thin film electrodes is a promising material for both energy storage and optoelectronics application based on the electrochemical properties obtained. The material showed about 80% charge capacity retention after 1000 cycles.