Effects of Cu/In compositional ratio on the characteristics of CuInS 2 absorber layers prepared by sulfurization of metallic precursors

Seung Hwan Lee, Seung Wook Shin, Jun Hee Han, Jeong Yong Lee, Myeong Gil Kang, G. L. Agawane, Jae Ho Yun, Jong Ha Moon, Jin Hyeok Kim

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

This paper investigates the effects of the Cu/In compositional ratio on morphological, structural and optical properties of CuInS 2 (CIS) absorber layers formed by sulfurization of In/Cu stacked precursors. In/Cu stacked precursors were prepared on Mo-coated soda-lime glass substrates by DC magnetron sputtering method. The Cu/In compositional ratio in the precursor thin film was varied from 0.55 to 1.44. The as-deposited stacked precursor thin films were sulfurized using a tubular furnace annealing system in a mixture of N 2 (95%) + H 2S (5%) atmosphere at 450°C for 1 hour. X-ray diffraction patterns and Raman spectra results showed that the sulfurized thin films contained both tetragonal CIS and a Cu-based secondary phase, except for the film with a Cu/In compositional ratio of 0.55. Field emission-scanning electron microscopy study showed that the microstructure of the sulfurized CIS thin films became denser with increasing Cu/In compositional ratio. Optical properties of the CIS thin films showed that all the CIS thin films had a good absorption coefficient over 10 4 cm -1 in the visible region. The direct band gap energy of the sulfurized CIS thin films decreased from 1.39 eV to 1.08 eV with increasing Cu/In compositional ratio. These results demonstrated the effect of the Cu/In compositional ratio on the properties of the CIS thin films and the consequent importance of precisely controlling the metal ratio in the precursor film in order to control the properties of absorber layers in thin film solar cells.

Original languageEnglish (US)
Pages (from-to)191-197
Number of pages7
JournalElectronic Materials Letters
Volume8
Issue number2
DOIs
StatePublished - Apr 1 2012

Keywords

  • Cu/In compositional ratio
  • CuInS (CIS)
  • Thin Film Solar Cells (TFSCs)
  • metallic precursor
  • sulfurization

Fingerprint Dive into the research topics of 'Effects of Cu/In compositional ratio on the characteristics of CuInS <sub>2</sub> absorber layers prepared by sulfurization of metallic precursors'. Together they form a unique fingerprint.

Cite this