Solar Cells with Epitaxial or Gas Phase Diffused Emitters Above 21% Efficiency

Rachow, Thomas; Milenkovic, Nena; Steinhauser, Bernd; Benick, Jan; Janz, S.; Hermle, Martin; Reber, S.

doi:10.1016/j.egypro.2015.07.077

Cited by 10 publications

(5 citation statements)

References 5 publications

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“…The throughput of emitter formation can be increased in the case of batch processing with a gas dopant source (e.g., POCl 3 ) by depositing at lower pressure. 47 This process can also be completely replaced by ion implantation 48,49 or chemical vapor deposition (CVD) either of a dopant source, 50 a doped epitaxial silicon layer, 51 or a polysilicon layer. 52 CVD and implant emitter formation also obviate the need for edge isolation because they are single-sided processes.…”

Section: Papermentioning

confidence: 99%

Economically sustainable scaling of photovoltaics to meet climate targets

Wilson¹,

Needleman²,

Poindexter³

et al. 2017

2017 IEEE 44th Photovoltaic Specialist Conference (PVSC)

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To meet climate targets, power generation capacity from photovoltaics (PV) in 2030 will have to be much greater than is predicted from either steady state growth using today's manufacturing capacity or industry roadmaps. Analysis of whether current technology can scale, in an economically sustainable way, to sufficient levels to meet these targets has not yet been undertaken, nor have tools to perform this analysis been presented. Here, we use bottom-up cost modeling to predict cumulative capacity as a function of technological and economic variables. We find that today's technology falls short in two ways: profits are too small relative to upfront factory costs to grow manufacturing capacity rapidly enough to meet climate targets, and costs are too high to generate enough demand to meet climate targets. We show that decreasing the capital intensity (capex) of PV manufacturing to increase manufacturing capacity and effectively reducing cost (e.g., through higher efficiency) to increase demand are the most effective and least risky ways to address these barriers to scale. We also assess the effects of variations in demand due to hard-to-predict factors, like public policy, on the necessary reductions in cost. Finally, we review examples of redundant technology pathways for crystalline silicon PV to achieve the necessary innovations in capex, performance, and price. Broader context To reduce CO 2 emissions enough over the next fifteen years and avoid the worst effects of climate change will require dramatic increases in the deployment of renewable energy, photovoltaics (PV) in particular. Climate action plans call for 2-10 terawatts (TW) of PV by 2030. Current manufacturing capacity could supply enough for 1 TW of cumulative installations at the end of this period, implying that growth in manufacturing capacity is necessary. Industry roadmaps project up to 2.6 TW but largely fail to assess whether these targets are economically feasible with today's PV module technology. Addressing the question of what technological innovations, if any, would enable rapid manufacturing scale-up requires a conceptual advance in modeling methodology. We address this challenge by coupling three industry-validated models: a bottom-up cost model, an economically sustainable growth-rate calculator, and a constraining demand curve. This approach enables us to determine the sensitivity of PV industry growth to specific technological and economic variables, considering both their effect on the ratio of up-front factory costs to revenue and demand as a function of PV module price. Shifting the demand curve enables us to consider the effects of different policy decisions, like a carbon tax or deployment subsidies.

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Section: Papermentioning

confidence: 99%

Economically sustainable scaling of photovoltaics to meet climate targets

Wilson¹,

Needleman²,

Poindexter³

et al. 2017

2017 IEEE 44th Photovoltaic Specialist Conference (PVSC)

View full text Add to dashboard Cite

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“…They also showed that they can selectively grow the epitaxial layer. Rachow et al produced a 21% efficient PERL solar cell by using phosphorus doped epitaxial emitter grown by APCVD [7]. This proves that epitaxially grown emitters can potentially replace diffused emitters in high performance IBC solar cells to simplify the process flow and hence reduce costs.…”

Section: Introductionmentioning

confidence: 98%

Junction Formation With HWCVD and TCAD Model of an Epitaxial Back-Contact Solar Cell

Rahman

Nawabjan

Tarazona³

et al. 2016

IEEE J. Photovoltaics

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Abstract-In this work we present morphological and electrical characteristics of a junction formed of Si P-type films deposited on an N-type silicon wafer using a hot wire chemical vapour deposition tool. We describe the fabrication process, and study the influence of diborane flow and post-process annealing in improving junction characteristics. Our morphological studies undertaken using atomic force microscopy show that the initial deposition suffered from voids rather than being a uniform film, however this improves significantly under our annealing treatment. The improvement in morphology was observed in the electrical characteristics, with estimated Voc doubling and rectification of the junction improving by several orders of magnitude. Fitting of the current-voltage curves to a two diode model, showed that increasing the diborane flow in the process helps reduce the saturation current and ideality factors, whilst increasing the shunt resistance. ECV and QSSPC measurements are used to characterise the deposited films further. A solar cell device with a silicon epitaxy emitter is modelled using industry standard 3D modelling tools and input parameters from experimental data, and the impact of defects is studied. A potential efficiency approaching 25% is shown to be feasible for an optimised device.

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“…For PassDop contacts, already the dielectric passivation is opened with the laser process and the Al layer is deposited afterwards. For further information about LFC [12] and PassDop contacts [13], [14], the reader is referred to Si literature. In both cases, the laser process leads to a highly p-type (p + ) doped region under each contact point, realized by Al atoms for LFC contacts and by Boron atoms for PassDop contacts.…”

Section: Introductionmentioning

confidence: 99%

Passivated, Highly Reflecting, Laser Contacted Ge Rear Side for III-V Multi-Junction Solar Cells

Weiss

Schön

Höhn

et al. 2021

IEEE J. Photovoltaics

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This article describes the successful integration of a passivated, highly reflecting Ge rear side into a III-V multijunction solar cell. The use of lowly doped Ge and the new rear side leads to the aimed increase in Ge cell current up to 1.6 mA.cm −2 , demonstrated by external quantum efficiency and I-V measurements. For the contact formation, two different types of laser processes were conducted and evaluated-the laser fired contact route and the PassDop route. In both cases, the formation of a local back surface field preserves the passivation of the contact points. A laser pitch and laser power variation leads to a good performing back contact. The passivation effect is proven experimentally and is qualitatively accessed with cell simulations.

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Solar Cells with Epitaxial or Gas Phase Diffused Emitters Above 21% Efficiency

Cited by 10 publications

References 5 publications

Economically sustainable scaling of photovoltaics to meet climate targets

Economically sustainable scaling of photovoltaics to meet climate targets

Junction Formation With HWCVD and TCAD Model of an Epitaxial Back-Contact Solar Cell

Passivated, Highly Reflecting, Laser Contacted Ge Rear Side for III-V Multi-Junction Solar Cells

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