Influence of Cu dopant on the optical and electrical properties of spray deposited tin sulphide thin films

• Optical and electrical properties of Cu doped SnS films have been investigated.
• Band gap values decreased from 1.55 to 1.37 eV as doping concentration increased.
• The PL showed a red-shift of the band gap and a minimum resistivity of 5.94 Ω cm.

Copper doped tin sulphide (SnS: Cu) thin films have been prepared by the spray pyrolysis technique at the substrate temperature of 350 °C. The optical and electrical properties of the films were studied as a function of copper dopant concentration (up to 10 at.%). The optical measurements showed the energy band gap, refractive index and extinction co-efficient values varied with increase in Cu concentration and the PL spectra showed the strong emission peak around at 765 nm. The film has the lowest resistivity while higher carrier concentration and mobility were obtained at 8 at.% of Cu.