TY - JOUR
T1 - Charge-carrier dynamics in polycrystalline thin-film CuIn1-xGaxSe2 photovoltaic devices after pulsed laser excitation
T2 - Interface and space-charge region analysis
AU - Kuciauskas, Darius
AU - Li, Jian V.
AU - Kanevce, Ana
AU - Guthrey, Harvey
AU - Contreras, Miguel
AU - Pankow, Joel
AU - Dippo, Pat
AU - Ramanathan, Kannan
PY - 2015/5/14
Y1 - 2015/5/14
N2 - 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.
AB - 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.
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U2 - 10.1063/1.4921011
DO - 10.1063/1.4921011
M3 - Article
SN - 0021-8979
VL - 117
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 18
M1 - 185102
ER -