Suitability of SnS thin films for photovoltaic application due to the existence of persistent photocurrent

Abstract

Tin sulfide (SnS) is a layered compound that retains its structure when deposited as thin films by thermal evaporation. The films thus obtained were found to have p-type conductivity, as confirmed by the hot-spot method. The films were found to have oriented growth with the direction of orientation changing with film thickness. The film's morphology was also found to change with orientation. The poor conductivity of the thicker samples made it difficult to make photoconductivity characterization, however, unlike reported studies in the literature, the thinner samples showed photosensitivity to be defect dependent and independent of film thickness and grain size with a high-persistent photocurrent. With their absorptivity, photosensitivity, optimum bandgap, and traps within the bandgap giving the charge carriers a longer lifetime, thin samples of tin sulfide give adequate scope for designing efficient photovoltaics.