Son, Yu-Seung Yu, Hyeonggeun Park, Jong-Keuk Kim, Won Mok Ahn, Seung-Yeop Choi, Wonjun Kim, Donghwan Jeong, Jeung-hyun 2024-01-19T21:01:54Z 2024-01-19T21:01:54Z 2021-09-02 2019-01-24 1932-7447 https://pubs.kist.re.kr/handle/201004/120452 Development of transparent-conducting oxide (TCO) back contact for Cu(In,Ga)Se-2 (GIGS) absorber is crucial for bifacial CIGS photovoltaics. However, inherent GaOx formation at the TCO/GIGS 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 GaOx formation. Na incorporation from the glass substrate during the GaOx forming phase created defective states at the interface, which allowed efficient hole extraction from CIGS, while post Na treatment after GaOx formation did not play such a role. Furthermore, we discovered that an almost GaOx-free interface could be made by reducing the underlying ITO film thickness, which revealed that ITO/CIGS junction is inherently Schottky. In the GaOx-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. English American Chemical Society FILM SOLAR-CELLS Control of Structural and Electrical Properties of Indium Tin Oxide (ITO)/Cu(ln,Ga)Se-2 Interface for Transparent Back-Contact Applications Article 10.1021/acs.jpcc.8b11149 1 The Journal of Physical Chemistry C, v.123, no.3, pp.1635 - 1644 The Journal of Physical Chemistry C 123 3 1635 1644 scie scopus 000457067500014 2-s2.0-85060023085 Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science Article FILM SOLAR-CELLS CIGS thin-film solar cell transparent back contact Gallium Oxide Na doping effect