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    Understanding the role of sulfurization temperature and sulfur amount in two-stage fabricated Sb2S3 thin films for photodetection
    (Elsevier, 2026) Olgar, Mehmet Ali; Keser, Yasemen Ince; Cam, Meryem; Daday, Mine Taykurt; Yilmaz, Salih; Bacaksiz, Emin; Zan, Recep
    Sb2S3 thin films were fabricated via a two-stage process for photodetector applications. In the first stage, Sb thin films deposited by sputtering were sulfurized at various temperatures (350-425 degrees C) using a fixed sulfur amount (10 mg), and in the second, the sulfur amount (10-25 mg) was varied at 375 degrees C. The effects of sulfurization conditions on the chemical composition, crystal structure, surface morphology, optical, and electrical properties were systematically studied. This study establishes the critical role of sulfurization temperature and sulfur amount in determining the structural evolution and stoichiometry of Sb2S3 thin films, thereby enabling control over their photo-sensing performance. The optimal S/Sb ratio (approximate to 1.07-1.08) and crystallinity were achieved at 375 degrees C, yielding the large-grained, lower defect-free films with preferential (hk1) orientation. Increasing the sulfur amount enhanced the S/Sb ratio up to 1.43 but introduced an undesired (hk0) orientation beyond 20 mg. The sample prepared with 15 mg sulfur (SbS-375-15) exhibited favorable morphology, a proper bandgap (1.68 eV), the highest carrier concentration, and lowest resistivity, making it the best photodetector candidate. The corresponding device showed low dark current (<1 nA), high photocurrent (similar to 10 nA), fast response (rise/fall: 11.2/12.7 ms), sensitivity of 1090 %, detectivity of 2.45 x 10(6) Jones, and an external quantum efficiency (EQE) of 0.841 %, demonstrating the strong potential of Sb2S3 for high-performance photodetectors.
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    Öğe
    Unveiling improvements in structural, optical, and photodetection characteristics of CZTS thin films through Ag-doping
    (Elsevier, 2025) Rehman, Fazal; Yilmaz, Salih; Polat, Ismail; Bacaksiz, Emin; Zan, Recep; Olgar, Mehmet Ali
    The study investigated the characterization of photodetectors made from CZTS (Cu2ZnSnS4) thin films by introducing silver (Ag) as a dopant. CZTS thin films were grown on Mo-foil by two stage process, comprising sputter deposition of metallic precursor layers followed by sulfurization process employing Rapid Thermal Annealing (RTA) approach. The stacking order for the undoped and Ag-doped CZTS thin films were Substrate/ ZnS/Cu/Sn/Cu and Substrate/ZnS/Cu/Sn/Cu/Ag, respectively. Photodetectors (PDs) were fabricated using sputter deposition on glass, including CZTS, Ag-doped CZTS-5 (8 nm Ag), Ag-doped CZTS-10 (16 nm Ag), and Agdoped CZTS-15 (24 nm Ag). Various characterization methods were utilized to examine the prepared thin films, including Energy Dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), optical transmission, Photoluminescence (PL) and photodetection analyses. Among all devices, Ag-CZTS-10 PDs exhibited the best performance, showing a crystallite size (D) of 51.72 nm, band gap of 1.47 eV and favorable SEM surface morphology. For the photodetection characteristics, blue light at 443 nm and red light at 525 nm wavelength were used with an applied bias of 2V, and a light intensity of 17.3 mW/cm2. The highest responsivity (R) values recorded for Ag-CZTS-10-based PDs were 0.0024 A/W for blue and 0.0019 A/ W for red light. Additionally, the detectivity (D*) was 3.4 x 106 Jones for blue and 2.3 x 106 Jones for red light, while sensitivity (S) was 26 % for blue and 15 % for red light. This study successfully demonstrated, for the first time, the fabrication of low-cost, high-performance Ag-doped CZTS films-based PDs on glass substrates which hold promise for the development of cost-effective and efficient optoelectronic devices.