TY - JOUR
T1 - Nanoscale Growth Kinetics of Cu(In,Ga)Se2 Absorbers
AU - West, Bradley M.
AU - Stuckelberger, Michael
AU - Lai, Barry
AU - Maser, Jörg
AU - Bertoni, Mariana
N1 - Funding Information:
We would like to thank Sina Soltanmohammad, Lei Chen, and William Shafarman from the Institute of Energy Conversion at the University of Delaware for fabricating the CIGS precursor layers. We acknowledge funding from the U.S. Department of Energy under contract DE-EE0005848. Use of the Advanced Photon Source, Office of Science user facilities, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/10/11
Y1 - 2018/10/11
N2 - We investigate the kinetics of elemental segregation during the synthesis of Cu(In1-x,Gax)Se2 (CIGS) thin films via a rapid thermal growth process. Changes in elemental concentration are mapped rapidly via in situ X-ray fluorescence (XRF) microscopy. In situ XRF enables the quantification of Cu, In, Ga, and Se concentrations with 200 nm spatial resolution over a region of 7 μm × 7 μm, large enough to map multiple CIGS grains. Reacting elemental precursor stacks at 500, 550, and 600 °C, we find that copper is the driving force for α-CIGS phase formation at a rate of 17 nmol/cm2/min at 500 °C. Because of the thermal expansion of the substrate, cluster analysis and classification algorithms were employed to track compositionally similar regions over time and across samples measured at different temperatures. Beyond the direct application of these results for the optimization of CIGS manufacturing, these in situ experiments demonstrate the feasibility of quantitative compositional evaluation at the nanoscale during the synthesis of technologically relevant materials. In combination with advanced analysis methods, this example shows how correlative X-ray microscopy can contribute to the solution of the materials paradigm, relating synthesis to composition and properties at the nanoscale.
AB - We investigate the kinetics of elemental segregation during the synthesis of Cu(In1-x,Gax)Se2 (CIGS) thin films via a rapid thermal growth process. Changes in elemental concentration are mapped rapidly via in situ X-ray fluorescence (XRF) microscopy. In situ XRF enables the quantification of Cu, In, Ga, and Se concentrations with 200 nm spatial resolution over a region of 7 μm × 7 μm, large enough to map multiple CIGS grains. Reacting elemental precursor stacks at 500, 550, and 600 °C, we find that copper is the driving force for α-CIGS phase formation at a rate of 17 nmol/cm2/min at 500 °C. Because of the thermal expansion of the substrate, cluster analysis and classification algorithms were employed to track compositionally similar regions over time and across samples measured at different temperatures. Beyond the direct application of these results for the optimization of CIGS manufacturing, these in situ experiments demonstrate the feasibility of quantitative compositional evaluation at the nanoscale during the synthesis of technologically relevant materials. In combination with advanced analysis methods, this example shows how correlative X-ray microscopy can contribute to the solution of the materials paradigm, relating synthesis to composition and properties at the nanoscale.
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U2 - 10.1021/acs.jpcc.8b05062
DO - 10.1021/acs.jpcc.8b05062
M3 - Article
AN - SCOPUS:85054392291
SN - 1932-7447
VL - 122
SP - 22897
EP - 22902
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 40
ER -