Temperature Dependent Dark Conductivity: Insights into Defect Levels in ln₂S₃ and Graphene-doped ln₂S₃ Thin Films

Abstract Indium sulphide is a promising candidate for optoelectronic and solar cell applications. This study employs a cost-effective, indigenously developed setup to analyse defect levels in In 2 S 3 and graphene-doped In 2 S 3 thin films, which are key determinants of their electronic properties. In 2 S 3 was deposited using Chemical Bath Deposition (CBD), and graphene was incorporated into the thin films through a two-step process involving spin coating followed by annealing. Shallow defect levels at 33 meV, associated with indium interstitials, were detected, which contribute to the n-type behaviour of In 2 S 3 . Defect levels in the range of 12-25 meV were similar to those in chlorine-doped In 2 S 3 , while a deeper defect level at 52.75 meV, which is absent in pristine In 2 S 3 , plays a key role in the superior properties of the graphene-doped In 2 S 3 films, suggesting its potential for advanced optoelectronic applications.