Effect of dipping time on the properties of Sb2S3/Si heterojunction prepared by chemical bath deposition

The effect of dipping time on the structural, optical and electrical properties of Sb2S3 film deposited on the glass and silicon substrates by chemical bath deposition technique was studied. The values of the optical energy gap determined from optical absorption were in the range 2-2.5 eV indicating good tunability of the film energy gap in the visible region. X-ray diffraction XRD result confirms that the all deposited films are crystalline in nature with orthorhombic phase and the reflection peak intensity was found to be decreased as dipping time increase. Scanning electron microscope SEM investigation reveals that the film morphology and grain size are depending on the dipping time. The film deposited at 3 min reveals a porous structure and spherical microcrystalline particles distributed over plate-like crystallites structure was observed for a film deposited at a longer time. The elemental analysis of the film as a function of dipping time was investigated using energy dispersive x-ray EDX. The Hall mobility of the film has increased from 2 to 4.75 cm(2)V(-1)s(-1 )as dipping time increased from 3 to 9 min. It was found that the dipping time playing a vital role in controlling the figures of merit of n-Sb2S3/p-Si heterojunction photodetectors namely dark and illuminated current-voltage, responsivity and specific detectivity. Spectral responsivity findings show that the photodetectors have two peaks of response located at 500 and 700 nm. Energy band diagram of the Sb2S3/Si heterojunction was constructed.