Charge-carrier dynamics in polycrystalline thin-film CuIn1-xGaxSe2 photovoltaic devices after pulsed laser excitation: Interface and space-charge region analysis

Darius Kuciauskas, Jian V. Li, Ana Kanevce, Harvey Guthrey, Miguel Contreras, Joel Pankow, Pat Dippo, Kannan Ramanathan

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We used time-resolved photoluminescence (TRPL) spectroscopy to analyze time-domain and spectral-domain charge-carrier dynamics in CuIn1-xGaxSe2 (CIGS) photovoltaic (PV) devices. This new approach allowed detailed characterization for the CIGS/CdS buffer interface and for the space-charge region. We find that dynamics at the interface is dominated by diffusion, where the diffusion rate is several times greater than the thermionic emission or interface recombination rate. In the space-charge region, the electric field of the pn junction has the largest effect on the carrier dynamics. Based on the minority-carrier (electron) drift-rate dependence on the electric field strength, we estimated drift mobility in compensated CuIn1-xGaxSe2 (with x ≈ 0.3) as 22 ± 2 cm2(Vs)-1. Analysis developed in this study could be applied to evaluate interface and junction properties of PV and other electronic devices. For CIGS PV devices, TRPL spectroscopy could contribute to understanding effects due to absorber compositional grading, which is one of the focus areas in developing record-efficiency CIGS solar cells.

Original languageEnglish
Article number185102
JournalJournal of Applied Physics
Volume117
Issue number18
DOIs
Publication statusPublished - 2015 May 14

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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