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Layer-Dependent Photoresponse Optimization in Two-Dimensional SnS2 MSM Photodetectors.

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Title: Layer-Dependent Photoresponse Optimization in Two-Dimensional SnS2 MSM Photodetectors.
Authors: Qiu, Qi-Rui1 (AUTHOR), Chang, Sheng-Po2 (AUTHOR) changsp@nkust.edu.tw, Chang, Shoou-Jinn1 (AUTHOR), Chen, Jone-Fang1 (AUTHOR), Lai, Wei-Chih3 (AUTHOR)
Source: Journal of Electronic Materials. Aug2026, Vol. 55 Issue 8, p7094-7104. 11p.
Abstract: Two-dimensional (2D) tin disulfide (SnS2) photodetector with interdigitated electrodes was fabricated on a sapphire substrate via a precisely controllable synthesis route. Instead of random exfoliation, SnO2 thin films deposited by radiofrequency (RF) magnetron sputtering were systematically converted to layered SnS2 through a localized sulfurization process. This approach enabled precise control of the active layer thickness from two to five layers, allowing for a rigorous investigation of thickness-dependent optoelectronic properties. Then, Ni/Au top electrodes were fabricated by thermal evaporation to complete the process of photodetector. Structural and optical characterizations, including transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDS), Raman spectroscopy, x-ray diffraction (XRD), and photoluminescence (PL) confirmed high-quality crystalline formation. Devices with controlled thicknesses from two to five layers were systematically investigated. After being illuminated by a Xenon lamp from 300 nm to 650 nm, the I–V curves revealed a maximum photoresponse in the 525–550 nm band, corresponding to an estimated bandgap of 2.25–2.36 eV. Among the devices, the three-layer SnS2 achieved the best responsivity of ~3.95 A/W, sensitivity of 11.3, detectivity of 7.5 × 109 Jones, and an external quantum efficiency (EQE) of 42.5%. This work addresses a key limitation in previous studies, where the layer-dependent photoresponse of SnS2 photodetectors has been reported but lacks a systematic physical interpretation. In this study, we establish a clear correlation between the performance peak and the critical trade-off between optical absorption volume and carrier recombination dynamics. Furthermore, we identify an optimal three-layer configuration and demonstrate stable switching reproducibility with a rise time of 190 s and a decay time of 90 s. These findings provide a generalized and physically grounded design guideline for layer-optimized 2D SnS2 photodetection platforms. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:Two-dimensional (2D) tin disulfide (SnS2) photodetector with interdigitated electrodes was fabricated on a sapphire substrate via a precisely controllable synthesis route. Instead of random exfoliation, SnO2 thin films deposited by radiofrequency (RF) magnetron sputtering were systematically converted to layered SnS2 through a localized sulfurization process. This approach enabled precise control of the active layer thickness from two to five layers, allowing for a rigorous investigation of thickness-dependent optoelectronic properties. Then, Ni/Au top electrodes were fabricated by thermal evaporation to complete the process of photodetector. Structural and optical characterizations, including transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDS), Raman spectroscopy, x-ray diffraction (XRD), and photoluminescence (PL) confirmed high-quality crystalline formation. Devices with controlled thicknesses from two to five layers were systematically investigated. After being illuminated by a Xenon lamp from 300 nm to 650 nm, the I–V curves revealed a maximum photoresponse in the 525–550 nm band, corresponding to an estimated bandgap of 2.25–2.36 eV. Among the devices, the three-layer SnS2 achieved the best responsivity of ~3.95 A/W, sensitivity of 11.3, detectivity of 7.5 × 109 Jones, and an external quantum efficiency (EQE) of 42.5%. This work addresses a key limitation in previous studies, where the layer-dependent photoresponse of SnS2 photodetectors has been reported but lacks a systematic physical interpretation. In this study, we establish a clear correlation between the performance peak and the critical trade-off between optical absorption volume and carrier recombination dynamics. Furthermore, we identify an optimal three-layer configuration and demonstrate stable switching reproducibility with a rise time of 190 s and a decay time of 90 s. These findings provide a generalized and physically grounded design guideline for layer-optimized 2D SnS2 photodetection platforms. [ABSTRACT FROM AUTHOR]
ISSN:03615235
DOI:10.1007/s11664-026-12929-4