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

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.