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ARTICLE

FeS₂ Film Properties and FeS₂/Co-doped SnS₂ Heterojunction for Photovoltaics Applications

Naoual Houaidji¹, Kenza Kamli^2,*, Zakaria Hadef², Houssem Eddine Chouial³, Marwa Bendaia¹

1 Materials Physico-Chemistry Laboratory, Science and Technology Faculty, Chadli Bendjedid—El Tarf University, El Tarf, Algeria
2 Laboratory of Mechanical Engineering and Materials, Sciences Faculty, Physics Department, University 20 August 1955, Skikda, Algeria
3 Laboratory of study and research of condensed states (LEREC), Faculty of Sciences, University Badji Mokhtar, Annaba, Algeria

* Corresponding Authors: Kenza Kamli. Email: ,

Chalcogenide Letters 2026, 23(3), 7 https://doi.org/10.32604/cl.2026.076383

Received 19 November 2025; Accepted 09 February 2026; Issue published 03 April 2026

Abstract

We present a systematic investigation of FeS₂ thin films deposited by ultrasonic spray pyrolysis (USP) at different deposition times (15–40 min), with the aim of understanding their structural, optical, and electrical evolution and their suitability for heterojunction device applications. Particular attention is given to the integration of the optimized FeS₂ layer with a Co-doped SnS₂ bottom layer to form a p–n heterojunction. Structural analysis by X-ray diffraction reveals a transition from an amorphous/oxidized phase at short deposition times toward well-crystallized pyrite after 25 min, while the 40-min film exhibits the most intense reflections and the largest crystallite size. Optical investigations indicate a progressive increase in film thickness from 0.23 to 1.53 μm between 20 and 40 min, accompanied by a reduction in the apparent optical band gap from 2.34 eV to 1.60 eV, consistent with improved crystallinity and enhanced light absorption. Electrical measurements further show a decrease in resistivity with increasing deposition time, together with improved carrier mobility and higher carrier concentration, confirming the enhancement of transport properties. The optimized FeS₂ layer was subsequently coupled with a SnS₂:Co film to fabricate a heterostructure, and current–voltage measurements reveal a pronounced rectifying response, confirming junction formation and charge separation at the interface. These findings demonstrate that deposition time plays a key role in tailoring FeS₂ film properties and that the FeS₂/SnS₂:Co architecture constitutes a promising, low-cost heterojunction platform for future optoelectronic and photovoltaic device applications.

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Supplementary Material

Supplementary Material File

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