Local structure analysis of Cu(In,Ga)Se<sub>2</sub> by X‐ray fluorescence holography

Shirakata, Sho; Kitamura, Yuichi; Happo, Naohisa; Hosokawa, Shinya; Hayashi, Kouichi

doi:10.1002/pssc.201600171

Cited by 2 publications

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“…The decline of accurate τ bulk determination for higher doping levels is a significant limitation because doping N A ≥ 10 14 cm −3 is needed in photovoltaic devices where minority charge carrier collection is aided by the junction field. Arsenic‐doped CdTe devices have reached doping levels of 10 15 –10 16 cm −3 , [ 20–22 ] Cu(In,Ga)Se 2 (CIGS) solar cell doping levels are typically 10 15 –10 16 cm −3 due to intrinsic defects, [ 23–27 ] and doping in perovskite solar cells can exceed 10 16 cm −3 . [ 28 ] Therefore, bulk recombination lifetime determination in doped absorbers is relevant for multiple PV technologies.…”

Section: Introductionmentioning

confidence: 99%

Charge Carrier Lifetime Determination in Graded Absorber Solar Cells Using Time‐Resolved Photoluminescence Simulations and Measurements

et al. 2023

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Thin‐film photovoltaic device efficiencies are limited by carrier recombination, thus understanding recombination mechanisms is critical for performance improvements. Bulk minority carrier lifetime (τ bulk) is a critical parameter for solar cells but is difficult to determine in P–N junction devices, especially for high doping. As doping ≥1016 cm−3 is required for efficient drift‐charge‐carrier‐collection devices, a method for τ bulk determination in doped P–N junction devices is necessary. This work utilizes time‐resolved photoluminescence (TRPL) simulations to quantify bulk and interface recombination properties in highly doped, graded absorber CdSeTe structures. The two methods developed here for τ bulk determination include utilization of an instantaneous lifetime representation to guide TRPL fitting and direct comparison between measured and simulated decays. Simulations verified that both methods are valid for state‐of‐the‐art device architectures which include graded bandgap absorbers, graded doping, and graded lifetimes. Shifts in the dominant recombination mechanism are identified for sufficiently long τ bulk, where front and back interface quality plays a more prominent role. Evaluation of surface recombination velocities and conduction band offset illustrate electro‐optical advantages of a positive conduction band offset and highlight the necessity of improved interfaces as bulk quality in photovoltaic devices improves.

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Section: Introductionmentioning

confidence: 99%

Charge Carrier Lifetime Determination in Graded Absorber Solar Cells Using Time‐Resolved Photoluminescence Simulations and Measurements

et al. 2023

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X‐Ray Fluorescence Holography Analysis of Local Structure in CuInSe₂ and CuGaSe₂

Shirakata

Happo

Hosokawa

2019

Physica Status Solidi (a)

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X‐ray fluorescence holography (XFH) is carried out using a synchrotron radiation on CuInSe2 and CuGaSe2 single crystals, which is powerful for the investigation of local atomic structure by three‐dimensional atom image. Incident X‐ray energies (9.7–12.7 keV) are used to excite the Cu Kα fluorescent X‐ray. Atom images are regenerated by Fourier transformation. In the cation plane in CuInSe2 (z = 0), the cation atom spots observed are the 2nd (In), 4th (Cu), 8th (Cu), and 10th (In) – nearest neighbor (NN) of the central Cu atom. For the anion plane (z = c/8) of CuInSe2, Se atoms spots, 1st and 3rd NN of Cu, are observed. Se atom spots are seen to deviate from the regular tetrahedral position due to the bond length difference between Cu‐Se bond and In‐Se bond. In the CuGaSe2 epitaxial layer (300 nm) grown on (100) GaAs, the cation plane exhibits clear atom spots of Cu and Ga atoms up to10th (Ga) NN of Cu. In the anion plane (z = c/8), only 1st NN Se atom spots are observed, and those of 3rd NN atom spots are not been observed. These results are discussed with relation to the perturbation acting on the Se atoms.

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Local structure analysis of Cu(In,Ga)Se₂ by X‐ray fluorescence holography

Cited by 2 publications

References 15 publications

Charge Carrier Lifetime Determination in Graded Absorber Solar Cells Using Time‐Resolved Photoluminescence Simulations and Measurements

Charge Carrier Lifetime Determination in Graded Absorber Solar Cells Using Time‐Resolved Photoluminescence Simulations and Measurements

X‐Ray Fluorescence Holography Analysis of Local Structure in CuInSe₂ and CuGaSe₂

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Local structure analysis of Cu(In,Ga)Se2 by X‐ray fluorescence holography

Cited by 2 publications

References 15 publications

Charge Carrier Lifetime Determination in Graded Absorber Solar Cells Using Time‐Resolved Photoluminescence Simulations and Measurements

Charge Carrier Lifetime Determination in Graded Absorber Solar Cells Using Time‐Resolved Photoluminescence Simulations and Measurements

X‐Ray Fluorescence Holography Analysis of Local Structure in CuInSe2 and CuGaSe2

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Local structure analysis of Cu(In,Ga)Se₂ by X‐ray fluorescence holography

X‐Ray Fluorescence Holography Analysis of Local Structure in CuInSe₂ and CuGaSe₂