A study of SnS thin films and its suitability for photovoltaic application based on the existence of persistent photocurrent

TL;DR

This study investigates SnS thin films' structural, optical, and photocurrent properties, highlighting their potential for photovoltaic applications due to persistent photocurrent and favorable optical characteristics.

Contribution

It provides new insights into the persistent photocurrent in SnS thin films and models their refractive index using Sellmeir's equation, differing from previous models.

Findings

Thinner SnS films exhibit high persistent photocurrent independent of thickness.

Optimum band-gap and traps within the band-gap enhance charge carrier lifetime.

Sellmeir's model effectively describes the refractive index of SnS thin films.

Abstract

Tin Sulphide is a layered compound which retains its structure when deposited as thin films by thermal evaporation. The films were found to have oriented growth with the direction of orientation changing with film thickness. The film's morphology was found to change with orientation. The poor conductivity of the thicker samples made it difficult to make photocunductivity characterisation. However, unlike reported the thinner samples showed photo-sensitivity to be independent of film thickness and grain size with a high persistent photocurrent. With their absorption, photosensitivty, optimum band-gap and traps within the band-gap giving the charge carriers a longer life-time, thin samples of tin sulphide gives adequate scope designing efficient photovoltaics. The refractive index was modeled using Sellmeir's model, while most of the previous studies talk of Wemple-DiDomenico single oscillator model or Cauchy's dispersion relation. The Sellmeir's fitting parameters are reported which can be of use in ellipsometric studies.