Article The Energy Level Alignment at the Buffer/Cu(In,Ga)Se2 Thin‐Film Solar Cell Interface for CdS and GaOx

Donald Valenta ORCID ; Hasan Arif Yetkin ORCID ; Tim Kodalle ORCID ; Jakob Bombsch ORCID ; Raul Garcia‐Diez ORCID ; Claudia Hartmann ORCID ; Shigenori Ueda SAMURAI ORCID ; Roberto Félix ; Johannes Frisch ORCID ; Lucas Bodenstein‐Dresler ORCID ; Regan G. Wilks ORCID ; Christian A. Kaufmann ; Marcus Bär ORCID

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Citation
Donald Valenta, Hasan Arif Yetkin, Tim Kodalle, Jakob Bombsch, Raul Garcia‐Diez, Claudia Hartmann, Shigenori Ueda, Roberto Félix, Johannes Frisch, Lucas Bodenstein‐Dresler, Regan G. Wilks, Christian A. Kaufmann, Marcus Bär. The Energy Level Alignment at the Buffer/Cu(In,Ga)Se2 Thin‐Film Solar Cell Interface for CdS and GaOx. Advanced Materials Interfaces. 2024, 11 (13), .
SAMURAI

Description:

(abstract)

The energy level alignment at the GaOx/CIGSe and CdS/CIGSe interfaces are compared by means of direct and inverse photoemission. For the GaOx/CIGSe we find a (0.04 ± 0.07) eV (i.e., a small spike-like) conduction band offset (CBO) and a (-3.21 ± 0.19) eV (i.e., a large cliff-like) valence band offset (VBO), which suggests a nearly ideal charge-selective contact. The derived GaOx band gap of (4.80 ± 0.25) eV confirms its utility as a highly transparent buffer layer. However, the GaOx (with x derived to be 1.1 ± 0.1) exhibits considerable defect-related occupied states above the valence band maximum. It is proposed that these states may increase charge carrier recombination and decrease open circuit voltage in respective devices; also explaining why solar cells with standard CdS buffer outperform devices with GaOx buffer, despite less ideal electronic interface properties (CBO: [-0.18 ± 0.07] eV, VBO: [-0.98 ± 0.15] eV) and the smaller CdS band gap of (2.35 ± 0.22) eV.

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Keyword: thin-film solar cell, Cu(In,Ga)Se2, CdS, GaOx, interface, energy level alignment, hard and soft X-ray photoelectron spectroscopy

Date published: 2024-03-08

Publisher: Wiley

Journal:

  • Advanced Materials Interfaces (ISSN: 21967350) vol. 11 issue. 13

Funding:

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1002/admi.202301110

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Updated at: 2024-05-09 12:30:19 +0900

Published on MDR: 2024-05-09 12:30:20 +0900

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