Nanostructured SnS-Si hybrid photodetectors by pulsed laser processed nanocolloids

Abstract

This research investigates the fabrication of SnS-Si hybrids for photodetection and photocatalysis using nanocolloids of tin sulfide (SnS), monocrystalline silicon (Sim) and polycrystalline silicon (Sip) produced by laser-assisted techniques (pulsed laser fragmentation as well as ablation in liquid). Characterization of the nanocolloids and the hybrid thin films obtained by techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron Spectroscopy (XPS), Raman spectroscopy, UV–Visible spectroscopy and photoluminescence spectroscopy (PL) are presented in this work. Post-deposition annealing improved the material properties of the hybrid films and the films exhibited optical bandgaps between 1.51 and 1.68 eV, suitable for light detection. In the case of hybrid SnS-Si films, SnS-Sim showed two orders of current higher than the SnS-Sip films. The photocurrent dynamic curves (current vs time) and current-voltage (I–V) characteristics are investigated to verify the improved device performances. The photodetector parameters such as sensitivity, responsivity, detectivity are also reported. Compared with conventional SnS thin film devices, all the films (SnS and SnS-Si hybrids) in this work responded to illumination sources of wavelengths up to 1064 nm. This is one of the initial studies on hybrid devices with Si nanoparticles for photodetector applications. All the films showed ultra-short response/recovery times in the range of 400–800 ms and their photodetector parameters were recorded. The films demonstrated good stability and cyclic photocatalytic activity to visible light.