Structure, morphology, and photoresponse characteristics dependence on substrate nature of grown π-SnS films using chemical bath deposition

Abstract

Thin films suffer from insufficient strength and cannot be made self-holding. Hence, more convenient fabrication process onto proper holding substrate material is needed to achieve well-matching with the film material. This research work aims to investigation of the influence of the substrate nature on the evolution of the structure, morphology and photoresponse characteristics of tin monosulfide (π-SnS) films. The π-SnS films have been deposited through the simple and cost-effective chemical bath deposition technique onto PET, glass, and n-type Si wafer substrates. X-ray diffraction and Raman analyses confirm that the films crystallize within a cubic structure of SnS phase with polycrystalline nature. Field emission scanning electron microscopy observations reveal that the surfaces of PET and Si substrates are covered with irregular spherical grains with the presence of some nanoflakes. Conversely, the surface of the glass substrate is found to be entirely covered with high-density assembled nanoflakes. The dark current value has been found to increase significantly from pA up to μA; at 3 V bias voltage, the dark current values are 55 pA, 850 pA, and 3.5 μA for the photodetectors based on PET, glass, and Si substrates, respectively. Moreover, upon the near-infrared illumination at 750 nm, the fabricated photodetectors demonstrate good sensitivity and photoresponse time; at 3 V bias voltage, the sensitivity values are found to be 2591, 697, and 2982 for photodetectors onto PET, glass, and Si substrates, respectively. The obtained results demonstrate the critical role of substrate nature on the characteristics of the as-grown π-SnS films.