Optoelectronic Characteristics of In2S3-CNT Nanocomposite Thin Films for Photodetector Application

The present study reports the synthesis of photosensitive carbon nanotube (CNT) intercalated indium sulphide (In 2 S 3 ) nanocomposite thin films by using chemical bath deposition coupled with the spin coating technique. The impact of incorporation of CNT in In 2 S 3 thin films is compared with that of pure In 2 S 3 films and is discussed in detail by evaluating their structural, compositional, morphological, optical and photocurrent measurements. Structural and compositional analyses such as x-ray diffraction, x-ray photoelectron spectroscopy, Energy dispersive spectroscopy and Raman measurements ensure the successful integration of CNTs within the In 2 S 3 thin films. Remarkable variation in morphology from mesh fractal structure to spider web structure due to the intercalation of CNTs is observed in the scanning electron micrograph. Roughness and thickness of as-synthesized samples are determined by atomic force microscopy. The excellent conducting nature of CNTs induces an appreciable enhancement of conductivity (resistance decreased from 31.5 GΩ to 15.1 GΩ) in In 2 S 3 -CNT nanocomposite thin films with respect to that of pure films, and is estimated from I–V analysis. Photosensitivity, responsivity, detectivity and noise equivalent power of these films are measured to explore their suitability as a photodetectors. Photocurrent responses at room temperature of the In 2 S 3 -CNT nanocomposite thin films exhibit around 14 times better photosensitivity than that of pure films. Optical absorption studies indicate the reduction in optical bandgap (2.38–2.29 eV) due to the incorporation of CNT. Our results suggest that the In 2 S 3 -CNT nanocomposite thin film can be considered as a good choice for room temperature photodetector applications. Graphic abstract