Control of Structural and Electrical Properties of Indium Tin Oxide (ITO)/Cu(In,Ga)Se 2 Interface for Transparent Back-Contact Applications

Yu Seung Son, Hyeonggeun Yu, Jong Keuk Park, Won Mok Kim, Seung Yeop Ahn, Wonjun Choi, Donghwan Kim, Jeung Hyun Jeong

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Development of transparent-conducting oxide (TCO) back contact for Cu(In,Ga)Se 2 (CIGS) absorber is crucial for bifacial CIGS photovoltaics. However, inherent GaO x formation at the TCO/CIGS interface has hampered the photocarrier extraction. Here, by controlling the Na doping scheme, we show that the hole transporting properties at the indium-tin oxide (ITO)/CIGS back contact can be substantially improved, regardless of the GaO x formation. Na incorporation from the glass substrate during the GaO x forming phase created defective states at the interface, which allowed efficient hole extraction from CIGS, while post Na treatment after GaO x formation did not play such a role. Furthermore, we discovered that an almost GaO x -free interface could be made by reducing the underlying ITO film thickness, which revealed that ITO/CIGS junction is inherently Schottky. In the GaO x -free condition, post-Na treatment could eliminate the Schottky barrier and create ohmic junction due to generation of conducting paths at the interface, which is supported by our photoluminescence analysis.

Original languageEnglish
Pages (from-to)1635-1644
Number of pages10
JournalJournal of Physical Chemistry C
Issue number3
Publication statusPublished - 2019 Jan 24

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films


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