Current-Matched III–V/Si Epitaxial Tandem Solar Cells with 25.0% Efficiency

Fan, Shizhao; Yu, Zhengshan J.; Hool, Ryan D.; Dhingra, Pankul; Weigand, William A.; Kim, Mi‐Jung; Ratta, Erik D.; Li, Brian D.; Sun, Yukun; Holman, Zachary C.; Lee, Minjoo Larry

doi:10.1016/j.xcrp.2020.100208

Cited by 39 publications

(30 citation statements)

References 36 publications

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“…[ 8 ] In 2020, an epitaxial GaAsP/Si dual‐junction solar cell with a verified AM1.5g conversion efficiency of 23.4% has been presented by Lepkowski et al [ 9 ] Fan et al presented a similar GaAsP/Si design with an in‐house measured (uncertified) efficiency of 25.0%. [ 10 ] Both results show the intense research leading to a strong efficiency increase over the last years. In this work, we focus on the development on GaInP/GaAs/Si triple‐junction cells as they have an even higher efficiency potential than their dual‐junction counterparts.…”

Section: Introductionmentioning

confidence: 94%

Epitaxial GaInP/GaAs/Si Triple‐Junction Solar Cell with 25.9% AM1.5g Efficiency Enabled by Transparent Metamorphic Al_xGa_1−xAs_yP_1−y Step‐Graded Buffer Structures

et al. 2021

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III–V/Si multi‐junction solar cells are potential successors to the silicon single‐junction cell due to their efficiency potential of up to 40% in the radiative limit.[1] Herein, latest results of epitaxially integrated GaInP/GaAs/Si triple‐junction cells are presented. To reduce parasitic absorption losses, which have limited the current density in the Si bottom cell in the previous devices, transparent AlxGa1–xAsyP1–y step‐graded metamorphic buffers are investigated. Compared with previous GaAsyP1–y step‐graded buffers, the transmittance is enhanced significantly, while no significant impact on the threading dislocation density is observed. Implemented into a new triple‐junction solar cell, an increase in short‐circuit current density from 10.0 to 12.2 mA cm−2 is achieved, leading to a new record conversion efficiency of 25.9% under AM1.5g conditions.

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Section: Introductionmentioning

confidence: 94%

Epitaxial GaInP/GaAs/Si Triple‐Junction Solar Cell with 25.9% AM1.5g Efficiency Enabled by Transparent Metamorphic Al_xGa_1−xAs_yP_1−y Step‐Graded Buffer Structures

et al. 2021

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“…The Si band gap of 1.12 eV is close to the ideal value for a bottom cell (0.9–1.0 eV), and mono-Si cells have the potential to achieve the lowest LCOE of any tandem configuration. , However, there is still only a limited set of top cell materials known to be compatible with c-Si, and only a restricted number of cell and module configurations is considered feasible or industrially attractive, as reviewed recently. , In particular, the direct monolithic tandem approachi.e., on-wafer integration without additional substrates or adhesives, usually resulting in two-terminal (2T) devicesis regarded as the most scalable and compatible with current high-throughput industrial tools. However, so far, only two direct monolithic approaches have demonstrated AM 1.5G tandem efficiencies exceeding 20%: (1) perovskite/Si tandems, which have achieved an efficiency of 29.5% certified in 2020, and (2) epitaxial GaAsP/Si tandems based on GaP/Si templates on Si(100) substrates, with a 25.0% efficiency also reported in 2020 . In the first case, the long-term stability of organometal halide perovskites remains an open question .…”

Section: Introductionmentioning

confidence: 99%

“…(1) perovskite/Si tandems, which have achieved an efficiency of 29.5% certified in 2020, 10 and (2) epitaxial GaAsP/Si tandems based on GaP/Si templates on Si(100) substrates, with a 25.0% efficiency also reported in 2020. 11 In the first case, the long-term stability of organometal halide perovskites remains an open question. 12 In particular, a reduced longevity can severely impact the LCOE, compared to the 25-and 30year warranty at >92% performance currently achieved by new Si and CdTe modules, respectively.…”

Section: Introductionmentioning

confidence: 99%

Gettering in PolySi/SiO_x Passivating Contacts Enables Si-Based Tandem Solar Cells with High Thermal and Contamination Resilience

Assar

Martinho

Larsen

et al. 2022

ACS Appl. Mater. Interfaces

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Multijunction solar cells in a tandem configuration could further lower the costs of electricity if crystalline Si (c-Si) is used as the bottom cell. However, for direct monolithic integration on c-Si, only a restricted number of top and bottom cell architectures are compatible, due to either epitaxy or high-temperature constraints, where the interface between subcells is subject to a trade-off between transmittance, electrical interconnection, and bottom cell degradation. Using polySi/SiO x passivating contacts for Si, this degradation can be largely circumvented by tuning the polySi/SiO x stacks to promote gettering of contaminants admitted into the Si bottom cell during the top cell synthesis. Applying this concept to the low-cost top cell chalcogenides Cu 2 ZnSnS 4 (CZTS), CuGaSe 2 (CGSe), and AgInGaSe 2 (AIGSe), fabricated under harsh S or Se atmospheres above 550 °C, we show that increasing the heavily doped polySi layer thickness from 40 to up to 400 nm prevents a reduction in Si carrier lifetime by 1 order of magnitude, with final lifetimes above 500 μs uniformly across areas up to 20 cm 2 . In all cases, the increased resilience was correlated with a 99.9% reduction in contaminant concentration in the c-Si bulk, provided by the thick polySi layer, which acts as a buried gettering layer in the tandem structure without compromising the Si passivation quality. The Si resilience decreased as AIGSe > CGSe > CZTS, in accordance with the measured Cu contamination profiles and higher annealing temperatures. An efficiency of up to 7% was achieved for a CZTS/Si tandem, where the Si bottom cell is no longer the limiting factor.

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“…Epitaxial growth of III–V materials on Si(100) substrates is highly desired for both, solar-to-electricity − and solar-to-fuel conversion. , As a transition layer between nonpolar Si substrates and polar III–V heterostructures, commonly a thin, pseudomorphic GaP buffer layer is deposited, due to its lattice constant close to that of Si. On these GaP/Si(100) virtual substrates, lattice-mismatched absorber structures can be grown strain-free on top of a metamorphic buffer with a stepwise increase of As , or In, , or directly lattice-matched with the introduction of small amounts of N into GaP(As). , The industrially preferred deposition technique for III–V-based devices is metalorganic chemical vapor deposition (MOCVD), as it ensures well-defined epitaxy with a high purity on a large scale.…”

Section: Introductionmentioning

confidence: 99%

A Route to Obtaining Low-Defect III–V Epilayers on Si(100) Utilizing MOCVD

Nandy

Paszuk

Feifel

et al. 2021

Crystal Growth & Design

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Low-defect III−V multilayer structures grown on Si(100) open opportunities for a wide range of cost-effective high-performance photovoltaic and optoelectronic devices. For that, (Al)GaP epilayers prepared almost lattice-matched on Si(100) substrates can serve as high-quality virtual substrates for subsequent heteroepitaxial growth. The evolution of crystal defects, such as stacking fault pyramids or threading dislocations, needs to be impeded already during the first preparation step, the III−V-on-Si nucleation, as they tend to propagate into the subsequently grown layers and increase nonradiative electron−hole recombination rates, which finally degrade the device performance. We establish a ternary GaP/AlP pulsed nucleation process on Si(100) substrates fabricated by metalorganic chemical vapor deposition, and compare it to the defect evolution from pure GaP nucleation layers (NLs). The entire procedure was optically monitored in situ using reflection anisotropy spectroscopy. Crystal defects were investigated by electron channeling contrast imaging. GaP grown on GaP/ AlP NLs exhibits drastically reduced densities of threading dislocations and stacking faults by 1 and 2 orders of magnitude, respectively, compared to buffer layers grown on binary GaP NLs. We observed that the surface morphology at the initial stage of growth of these buffer layers is significantly smoother compared to the buffer layers grown on pure GaP NLs using atomic force microscopy. The proposed nucleation procedure here is supposed to substantially improve the crystalline quality of III−V buffer layers integrated on Si(100) wafers.

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Current-Matched III–V/Si Epitaxial Tandem Solar Cells with 25.0% Efficiency

Cited by 39 publications

References 36 publications

Epitaxial GaInP/GaAs/Si Triple‐Junction Solar Cell with 25.9% AM1.5g Efficiency Enabled by Transparent Metamorphic Al_xGa_1−xAs_yP_1−y Step‐Graded Buffer Structures

Epitaxial GaInP/GaAs/Si Triple‐Junction Solar Cell with 25.9% AM1.5g Efficiency Enabled by Transparent Metamorphic Al_xGa_1−xAs_yP_1−y Step‐Graded Buffer Structures

Gettering in PolySi/SiO_x Passivating Contacts Enables Si-Based Tandem Solar Cells with High Thermal and Contamination Resilience

A Route to Obtaining Low-Defect III–V Epilayers on Si(100) Utilizing MOCVD

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Current-Matched III–V/Si Epitaxial Tandem Solar Cells with 25.0% Efficiency

Cited by 39 publications

References 36 publications

Epitaxial GaInP/GaAs/Si Triple‐Junction Solar Cell with 25.9% AM1.5g Efficiency Enabled by Transparent Metamorphic AlxGa1−xAsyP1−y Step‐Graded Buffer Structures

Epitaxial GaInP/GaAs/Si Triple‐Junction Solar Cell with 25.9% AM1.5g Efficiency Enabled by Transparent Metamorphic AlxGa1−xAsyP1−y Step‐Graded Buffer Structures

Gettering in PolySi/SiOx Passivating Contacts Enables Si-Based Tandem Solar Cells with High Thermal and Contamination Resilience

A Route to Obtaining Low-Defect III–V Epilayers on Si(100) Utilizing MOCVD

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Epitaxial GaInP/GaAs/Si Triple‐Junction Solar Cell with 25.9% AM1.5g Efficiency Enabled by Transparent Metamorphic Al_xGa_1−xAs_yP_1−y Step‐Graded Buffer Structures

Epitaxial GaInP/GaAs/Si Triple‐Junction Solar Cell with 25.9% AM1.5g Efficiency Enabled by Transparent Metamorphic Al_xGa_1−xAs_yP_1−y Step‐Graded Buffer Structures

Gettering in PolySi/SiO_x Passivating Contacts Enables Si-Based Tandem Solar Cells with High Thermal and Contamination Resilience