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ARTICLE

Annealing effect on the photocurrent response of SnS thin films prepared by the chemical spray pyrolysis method

D. Dekhil^a,*, H. Guessas^a, A. Nouri^a, S. Ullah^b

a Laboratory of Photonics Systems and Nonlinear Optics, Institute of Optics and Precision Mechanics, University Setif 1, Algeria
b Design and Manufacturing Institute (IDF)-Polytechnic University of Valencia (UPV), Valencia, Spain

* Corresponding Author:

Chalcogenide Letters 2023, 20(8), 549-558. https://doi.org/10.15251/CL.2023.208.549

Received 12 May 2023; Accepted 01 August 2023;

Abstract

SnS thin films were synthesized using the spray pyrolysis method and then annealed at 350, 400, and 450°C. According to the crystallographic analysis, the obtained SnS thin films crystallized in the polycrystalline orthorhombic system. The grains measured 47, 66, and 37 nm for the samples annealed at 350, 400, and 450°C, respectively. SEM and AFM images indicate that the samples’ surfaces were completely covered. Thus, the grains of SnS nanostructures have a granular-like shape and vary in size depending on the annealing temperatures. The transmittance measurement shows that annealing the sample at 400 °C extends and improves its absorption range to 600 nm. The resulting band gap energies were 1.60 eV, 1.30 eV, and 2.55 eV for annealing at 350 °C, 400 °C, and 450 °C, respectively. Hall Effect measurements reveal that annealing SnS films at 400 °C enhances their electrical properties. The values of carrier mobility, conductivity, and carrier concentration are 1.678 ×10⁵Cm2/Vs, 9.756 ×10^-5Ω^-1cm^-1, and 3.168 ×10¹⁰Cm^-3, respectively. Additionally, the photocurrent response validates that all samples annealed at 350, 400, and 450 °C have p-type conductivity, with values of 13, 28, and 2.5 µA/Cm2, respectively. The best conductivity, carrier mobility, and photocurrent values are obtained by annealing at 400 °C. Therefore, SnS thin films can be an interesting choice for absorber layer applications in photovoltaic systems.

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Keywords

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