Determination of the Electrical Junction in Cu(In, Ga)Se2 and Cu2ZnSnSe4 Solar Cells with 20-nm Spatial Resolution

Chuanxiao Xiao, Chun Sheng Jiang, Helio Moutinho, Dean Levi, Mowafak Al-Jassim, Brian Gorman, Yanfa Yan

Research output: Contribution to conferencePaperpeer-review

Abstract

We located the electrical junction (EJ) of Cu(In, Ga)Se2 (CIGS) and Cu2ZnSnSe4 (CZTS) solar cells with ∼20-nm accuracy using a scanning capacitance spectroscopy (SCS) technique. A procedure was developed to prepare the cross-sectional samples and grow critical high-quality insulating layers for the SCS measurement. We found that CIGS has a buried homojunction with the EJ located at ∼40 nm inside the CIGS/CdS interface. An n-type CIGS was probed in the region 10-30 nm away from the interface. By contrast, the CZTS/CdS cells have a heterointerface junction with a shallower EJ (∼20 nm) than CIGS. The EJ is ∼20 nm from the CZTS/CdS interface, which is consistent with asymmetrical carrier concentrations of the p-CZTS and n-CdS in a heterojunction cell. The unambiguous determination of the junction locations helped explain the large open circuit voltage difference between the state-of-the-art devices of CIGS and CZTS.

Original languageAmerican English
Pages2298-2301
Number of pages4
DOIs
StatePublished - 18 Nov 2016
Event43rd IEEE Photovoltaic Specialists Conference, PVSC 2016 - Portland, United States
Duration: 5 Jun 201610 Jun 2016

Conference

Conference43rd IEEE Photovoltaic Specialists Conference, PVSC 2016
Country/TerritoryUnited States
CityPortland
Period5/06/1610/06/16

Bibliographical note

Publisher Copyright:
© 2016 IEEE.

NREL Publication Number

  • NREL/CP-5K00-65748

Keywords

  • CIGS
  • CZTS
  • electrical junction
  • scanning capacitance spectroscopy

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