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Thickness-Dependently Enhanced Photodetection Performance of Vertically Grown SnS2 Nanoflakes with Large Size and High Production

Jia, Xiansheng, Tang, Chengchun, Pan, Ruhao, Long, Yunze, Gu, Changzhi, Li, Junjie
ACS applied materials & interfaces 2018 v.10 no.21 pp. 18073-18081
crystals, nanomaterials, sensors (equipment), silicon
Photodetection based on two-dimensional (2D) SnS₂ has attracted growing interest due to its superiority in response rate and responsivity, but high-quality growth and high performance photodetection of 2D SnS₂ still face great challenges. Here, high-quality SnS₂ nanoflakes with large-size and high-production are vertically grown on an Si substrate by a modified CVD method, having an average size of 30 μm with different thicknesses. Then a single SnS₂ nanoflake-based phototransistor was fabricated to obtain a high current on/off ratio of 10⁷ and excellent performance in photodetection, including fast response rates, low dark current, and high responsivity and detectivity. Specifically, the SnS₂ nanoflakes show thickness-dependent photodetection capability, and a highest responsivity of 354.4 A W⁻¹ is obtained at the average thickness of 100.5 nm. A sensitized process using an HfO₂ nanolayer can further enhance the responsivity up to 1922 A W⁻¹. Our work provides an efficient path to select SnS₂ crystal samples with the optimal thickness as promising candidates for high-performance optoelectronic applications.