Flexible and high-performance broadband nanoflowers tin sulfide photodetector

A significant prerequisite for the development of a high-performance photodetector remains its low dark current value, because it promotes sensitivity and signal-to-noise ratio, in addition to low detectability light power density. Nevertheless, the fabricated photodetectors, which are based on deposited tin sulfide (SnS) films onto a flexible (PET at pH 5) and glass substrates, exhibited relatively high dark current values around (0.2 µA) and (several µA), respectively. This study proposes a novel approach for a better control of the photoresponse characteristics of nanostructured SnS film which resulted from reducing the deposition growth rate by adjusting the pH of the reaction solution to 5.8. The film was deposited onto a flexible substrate of polyethylene terephthalate (PET) using an inexpensive chemical bath deposition method. The as-fabricated photodetector exhibited a low dark current value approximately (~ 24 nA) at 5 V bias voltage and a good response in a broad range covering the UV up to the near-infrared. Besides, light-emitting diodes (380, 530, 750, and 850 nm) were used to investigate the photoresponse characteristics of the photodetector. The latter manifested fast photoresponse times (rise and decay) and good sensitivity for all used illumination wavelengths. Furthermore, under various illumination power densities of 850 nm, the photocurrent manifested a good dependence upon power density. Based on the obtained excellent photoresponse characteristics, this photodetector is promising for the photoelectronic flexible device in the UV–Vis–NIR range.