Stoichiometry control in Cu2ZnSnS4 thin films grown by pulsed laser deposition

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review

6 Scopus Citations
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Detail(s)

Original languageEnglish
Pages (from-to)90-96
Journal / PublicationMaterials Chemistry and Physics
Volume205
Online published30 Oct 2017
Publication statusPublished - 1 Feb 2018

Abstract

We synthesized Cu2ZnSnS4 (CZTS) thin films on soda lime glass substrates using pulsed laser deposition. Deposition parameters and sputtering target compositions were varied in order to optimize the compositions and morphologies of the CZTS films. At room temperature, films deposited using a sputtering target composition of Cu1.83Zn1.16Sn0.95S4.05, consisting of the nominally desired metal ratios and excess sulfur, were found to be heavily Sn-rich and S-deficient. By reducing the Sn concentrations in the sputtering targets, film compositions could be adjusted to the desired stoichiometries. Laser fluence was found to strongly influence the Cu:Zn ratios in the films, with a clear laser ablation threshold visible at ∼2.5 J/cm2, above which the film stoichiometry did not significantly change. Increasing the pulse repetition rate slightly increased the relative Zn and S concentrations in the films but also introduced micron-sized cracks. Substrate temperature was shown to have a significant effect on the composition and quality of the deposited films. While smoother films with larger-width grains were achieved at temperatures of 400 and 500 °C, significant losses in Zn and Sn were observed. Recommendations on the optimized deposition parameters and sputtering target compositions are presented.

Research Area(s)

  • Cu2ZnSnS4 absorber, Pulsed laser deposition, Raman spectroscopy, Rutherford backscattering