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

doi:10.1021/acs.jpcc.8b11149

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 journal › Article › peer-review

26 Citations (Scopus)

Abstract

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 language	English
Pages (from-to)	1635-1644
Number of pages	10
Journal	Journal of Physical Chemistry C
Volume	123
Issue number	3
DOIs	https://doi.org/10.1021/acs.jpcc.8b11149
Publication status	Published - 2019 Jan 24

Bibliographical note

Funding Information:
This work was supported by the internal program of Korea Institute of Science and Technology (KIST), by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) (Nos. 20153030013060, 20158520000060), and by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2016M1A2A2936782) of Republic of Korea.

Publisher Copyright:
© 2019 American Chemical Society.

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
General Energy
Physical and Theoretical Chemistry
Surfaces, Coatings and Films

Access to Document

10.1021/acs.jpcc.8b11149

Cite this

Son, Y. S., Yu, H., Park, J. K., Kim, W. M., Ahn, S. Y., Choi, W., Kim, D., & Jeong, J. H. (2019). Control of Structural and Electrical Properties of Indium Tin Oxide (ITO)/Cu(In,Ga)Se ₂ Interface for Transparent Back-Contact Applications Journal of Physical Chemistry C, 123(3), 1635-1644. https://doi.org/10.1021/acs.jpcc.8b11149

Control of Structural and Electrical Properties of Indium Tin Oxide (ITO)/Cu(In,Ga)Se ₂ Interface for Transparent Back-Contact Applications . / Son, Yu Seung; Yu, Hyeonggeun; Park, Jong Keuk et al.
In: Journal of Physical Chemistry C, Vol. 123, No. 3, 24.01.2019, p. 1635-1644.

Research output: Contribution to journal › Article › peer-review

Son, YS, Yu, H, Park, JK, Kim, WM, Ahn, SY, Choi, W, Kim, D & Jeong, JH 2019, ' Control of Structural and Electrical Properties of Indium Tin Oxide (ITO)/Cu(In,Ga)Se ₂ Interface for Transparent Back-Contact Applications ', Journal of Physical Chemistry C, vol. 123, no. 3, pp. 1635-1644. https://doi.org/10.1021/acs.jpcc.8b11149

Son YS, Yu H, Park JK, Kim WM, Ahn SY, Choi W et al. Control of Structural and Electrical Properties of Indium Tin Oxide (ITO)/Cu(In,Ga)Se ₂ Interface for Transparent Back-Contact Applications Journal of Physical Chemistry C. 2019 Jan 24;123(3):1635-1644. doi: 10.1021/acs.jpcc.8b11149

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

abstract = " 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.",

author = "Son, {Yu Seung} and Hyeonggeun Yu and Park, {Jong Keuk} and Kim, {Won Mok} and Ahn, {Seung Yeop} and Wonjun Choi and Donghwan Kim and Jeong, {Jeung Hyun}",

note = "Funding Information: This work was supported by the internal program of Korea Institute of Science and Technology (KIST), by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) (Nos. 20153030013060, 20158520000060), and by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2016M1A2A2936782) of Republic of Korea. Publisher Copyright: {\textcopyright} 2019 American Chemical Society.",

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N2 - 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.

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