Title: Effect of deposition temperature on structural, optical and electrical properties of chemically deposited thermochromic Cu₂HgI₄ thin films

Authors: A.M. Mansour; I.M. El Radaf; G.M. Mahmoud

Addresses: Solid State Physics Department, Physics Research Division, National Research Centre, 33 El-Bohouth St., Dokki, Giza, 12622, Egypt; Department of Flexible Electronics, Center of Microelectronics in Provence, Mines Saint-Etienne, F-13541 Gardanne, France ' Electron Microscope and Thin Films Department, Physics Research Division, National Research Centre, 33 El-Bohouth St., Dokki, Giza, 12622, Egypt; Materials Physics and Energy Laboratory, College of Sciences and Arts, Qassim University, ArRass 51921, KSA ' Solid State Physics Department, Physics Research Division, National Research Centre, 33 El-Bohouth St., Dokki, Giza, 12622, Egypt

Abstract: Copper mercury tetraiodide thin films were grown by the chemical bath deposition technique at different deposition temperatures varying from 300 K to 345 K. The structural properties of the prepared Cu₂HgI₄ thin films show that the Cu₂HgI₄ films have a polycrystalline nature. The compositional analysis confirmed the nearly stoichiometric structure of the deposited Cu₂HgI₄ thin films. Homogeneous and regular surface morphology, including of circular-shaped grains with a size range from 31 to 46 nm, was revealed. Thermal stability and phase transition were studied by means of thermogravimetric analysis (TGA) and differential thermal analysis (DSC), respectively. The effects of deposition temperature on the optical properties and D.C. electrical conductivity of the Cu₂HgI₄ films have been studied. The films were found to have an indirect optical energy gap of values increases with increasing substrate temperature. The electrical conductivity increases with increasing temperature according to grain boundary trapping model.

Keywords: copper mercury tetraiodide; differential thermal analysis; TGA; thermogravimetric analysis; optical; electrical conductivity.

DOI: 10.1504/IJMMP.2019.102223

International Journal of Microstructure and Materials Properties, 2019 Vol.14 No.5, pp.462 - 477

Received: 15 Mar 2019
Accepted: 27 Apr 2019
Published online: 11 Sep 2019 *

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