Spray pyrolysis deposition of indium sulphide thin films

• Published in: Thin solid films Vol. 519; no. 10; pp. 3055 - 3060
• Main Authors: Otto, K., Katerski, A., Mere, A., Volobujeva, O., Krunks, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2011; Elsevier
• Subjects: Chemical spray pyrolysis; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; EDS; Exact sciences and technology; In 2S 3; Indium oxides; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Spectra; Spray coating techniques; Spray pyrolysis; Sprayers; Sprays; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film; Thin film structure and morphology; Thin films; X-ray photoelectron spectroscopy; X-rays; XPS; XRD; EDS; Optical properties; In 2S 3; XPS; XRD; Chemical spray pyrolysis; Thin film; Beta phase; Transparency; In; XPS EDS; Thin films; S; Aqueous solutions; Optical transmission; Oxidation; Absorption spectra; Indium sulfide; Temperature dependence; Scanning electron microscopy; Pyrolysis; Annealing; Tetragonal lattices; Chlorine; Indium chloride; Spray coatings; Indium; Dispersive spectrometry; Layer thickness; Indium oxide; X-ray photoelectron spectra
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2010.12.027

In 2S 3 thin films were grown by the chemical spray pyrolysis (CSP) method using the pneumatic spray set-up and compressed air as a carrier gas. Aqueous solutions containing InCl 3 and SC(NH 2) 2 at a molar ratio of In/S = 1/3 and 1/6 were deposited onto preheated glass sheets at substrate temperatures T s = 205–410 °C. The obtained films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM,) optical transmission spectra, X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS). According to XRD, thin films deposited at T s = 205–365 °C were composed of the (0 0 12) orientated tetragonal β-In 2S 3 phase independent of the In/S ratio in the spray solution. Depositions performed at T s = 410 °C led to the formation of the In 2O 3 phase, preferably when the 1/3 solution was sprayed. Post-deposition annealing in air indicated that oxidation of the sulphide phase has a minor role in the formation of In 2O 3 at temperatures up to 450 °C. In 2S 3 films grown at T s below 365 °C exhibited transparency over 70% in the visible spectral region and E g of 2.90–2.96 eV for direct and 2.15–2.30 eV for indirect transitions, respectively. Film thickness and chlorine content decreased with increasing deposition temperatures. The XPS study revealed that the In/S ratio in the spray solution had a significant influence on the content of oxygen (Me–O, BE = 530.0 eV) in the In 2S 3 films deposited in the temperature range of 205–365 °C. Both XPS and EDS studies confirmed that oxygen content in the films deposited using the solution with the In/S ratio of 1/6 was substantially lower than in the films deposited with the In/S ratio of 1/3.