Bandgap Engineering of Cu(In1-xGax)Se2 Absorber Layers Fabricated using CuInSe2 and CuGaSe2 Targets for One-Step Sputtering Process

Mowafak Al-Jassim, Jae-Cheol Park, Jeon-Ryang Lee, Tae-Won Kim

Research output: Contribution to journalArticlepeer-review

22 Scopus Citations

Abstract

We have demonstrated that the bandgap of Cu(In1-xGax)Se2(CIGS) absorber layers was readily controlled by using a one-step sputtering process. CIGS thin-film sample libraries with different Ga/(In + Ga) ratios were synthesized on soda-lime glass at 550°C using a combinatorial magnetron sputtering system employing CuInSe2(CIS) and CuGaSe2(CGS) targets. Energy-dispersive X-ray fluorescence spectrometry (EDS-XRF) confirmed that the CIGS films had different Ga/(In + Ga) ratios, which were varied by the sample configuration on the substrate and ranged from 0.2 to 0.9. X-ray diffraction and Raman spectroscopy revealed that the CIGS films had a pure chalcopyrite phase without any secondary phase such as Cu-Se or ordered vacancy compound (OVC), respectively. Furthermore, we found that the optical bandgap energies of the CIGS films determined by transmittance measurements ranged from 1.07 eV to 1.53 eV as the Ga/(In + Ga) ratio increased from 0.2 to 0.9, demonstrating that the one-step sputtering process using CIS and CGS targets is another simple route to control the bandgap energy of the CIGS absorber layer.

Original languageAmerican English
Pages (from-to)3541-3549
Number of pages9
JournalOptical Materials Express
Volume6
Issue number11
DOIs
StatePublished - 2016

Bibliographical note

Publisher Copyright:
© 2016 Optical Society of America.

NREL Publication Number

  • NREL/JA-5K00-67515

Keywords

  • absorber layers
  • bandgap
  • sputtering
  • thin films

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