RESEARCH CENTER JLICH GMBH, JLICH, GERMANY INSTITUTE OF ENERGY AND - - PowerPoint PPT Presentation

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Sep 22, 2022 525 likes •737 views

RESEARCH CENTER JLICH GMBH, JLICH, GERMANY INSTITUTE OF ENERGY AND CLIMATE RESEARCH 5 PHOTOVOLTAICS INNOVATION IN THIN-FILM MATERIAL AND PROCESSING FOR SILICON SOLAR CELL 25.02.2019 K.DING, A.LAMBERTZ, W.DUAN, M.POMASKA, A.GAD, K.BITTKAU

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RESEARCH CENTER JÜLICH GMBH, JÜLICH, GERMANY INSTITUTE OF ENERGY AND CLIMATE RESEARCH 5 – PHOTOVOLTAICS

25.02.2019 K.DING, A.LAMBERTZ, W.DUAN, M.POMASKA, A.GAD, K.BITTKAU

INNOVATION IN THIN-FILM MATERIAL AND PROCESSING FOR SILICON SOLAR CELL

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RESEARCH IN GERMANY

22.03.2019 2

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RESEARCH CENTER JUELICH

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IEK-5 PHOTOVOLTAICS

Research groups: 6 Staff: ~100

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Helmholtz RC Jülich IEK-5 PV

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MOTIVATION SHJ

Silicon thin-film „DNA“ at IEK-5

Key expertise is application of novel material and process in SHJ solar cells

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  • Si thin-films
  • Si alloys
  • TCO films
  • Multijunction
  • Light management
  • Laser processing
  • …
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SHJ (c-Si) GROUP

Main collaborator for c-Si activities

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  • Establishing a baseline for

industrial sized (156 x 156 mm²) SHJ solar cells

  • Establishing a baseline for silicon

solar modules for vehicle integrated PV

  • Establishing a process and

characterization standard for passivated contact solar cells

  • Application of silicon alloys and

HWCVD processes in SHJ solar cells

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DEVICE TYPE

„Rear emitter M2 size SHJ solar cell

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  • µc-Si:H and µc-SiOx:H etc.
  • IWO, ITiO, AZO etc.
  • Smartwire
  • Thin wafers (<40 µm)
  • Pero-Si-Tandem
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SILICON HETEROJUNCTION BASELINE

For industrial sized SHJ solar cells

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STEP 1

Wafer pretreatment

STEP 2

Silicon deposition

STEP 3

TCO sputtering

STEP 4

Silver screen printing

STEP 5

Cell characterization

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SILICON HETEROJUNCTION BASELINE

For industrial sized SHJ solar cells

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  • High solar cell efficiency
  • Reproducible and homogeneous process
  • High throughput
  • Fast feed back
  • Industrial scalable tools
  • Established platforms

 Test materials and processes for ƞ > 25%

Jsc [mA/cm²] Voc [mV] 37.4 724 FF [%] ƞ [%] 78.8 21.4 200 400 600 10 20 30 40 Voltage [mV] Current density [mA/cm2]

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NANOCRYSTALLINE SILICON OXIDE

Transparent and conductive window layer

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  • Deposited by PECVD, both n- and p-type possible
  • Industrial compatible/transferable process
  • Fully compatible with SHJ solar cell technology
  • A. Richter, et.al. (2017) Sol. Energy Mater. Sol. Cells, 174, 196–201.
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NANOCRYSTALLINE SILICON OXIDE

Good uniformity of material properties

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2.0 2.1 2.2 2.3 2.4 2.0 2.1 2.2 2.3 2.4 E04 on a-position [eV] E04 on e-position [eV] 1E-8 1E-5 0.01 10 1E-8 1E-5 0.01 10  on a-position [S/cm]  on e-position [S/cm]

a e

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VEHICLE INTEGRATED PV

SHJ solar cell for integration in automobile industry

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New aspects on cell requirement:

  • High demand on aesthetics
  • Flexibility in cell size required

StreetScooter Audi

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MICROCRYSTALLINE SILCON CARBIDE

Transparent and low-T passivated contact

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  • Deposited by HWCVD
  • Low-T process compatible with SHJ
  • Highly transparent SiO2/SiC stack
  • High passivation quality
  • M. Pomaska, et.al. (2015) Thin Solid Films, 595, 217–220.

1014 1015 1016 1 10

effective minority carrier lifetime teff [ms] minority carrier density Dp [cm-3]

SiC/SiO2 passivation τeff(1015) = 2.2 ms iVoc = 731 mV

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TRANSPARENT PASSIVATED CONTACT

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η (%) Jsc (mA/c m²) FF (%) Voc (mV) Rs (Ωcm²) SiC/SiO2 19.7 38.7 71.5 712 2.1 Ref. 19.9 36.1 75.7 727 1.4 µc-SiC:H(n)/SiO2 passivation deteriorated during ITO sputtering  iVoc limited  Jsc decreased

First low-T transparent passivated contact

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POLY-SI PASSIVATED CONTACT

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Process chain: 1. growth of ca. 1.5 nm tunnel oxide 2. HWCVD n-doped layer (Si, SiO SiC) 3. furnace anneal @ 800-900 °C 4. deposition of ca. 80 nm SiNx layer 5. Screen print Ag-contacts 6. fire contacts @ 850 °C c-Si(n) SiOx a-/nc-Si:H(n) poly-Si(n+) SiNx Ag Ag

Currently best iVoc: 731 mV (with Rsheet = 142 Ω□ and deposition rate of 42 nm/min

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CHARACTERIZATION JOSEPH

Understanding the passivated contact

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SUMMARY

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  • Research Center Jülich works on SHJ and Pass. Con.
  • Key expertise is thin-film materials and processes for SHJ
  • Industrial sized processes
  • Unique Si-alloy materials and HWCVD processes
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ACKNOWLEDGEMENT

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Thank you for your attention!

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CATALYTIC DOPING

Post deposition treatment for SHJ solar cell

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  • Y. Liu, et.al., (2017) Thin Solid Films, 635, 63–65.
  • Good synergy by combining cat-

doping and SHJ technology

  • Post deposition treatment to

engineer the thin-films and the interfaces

  • Increase in P doping (ECV, SIMS)
  • Increase in lifetime (QSSPC)
  • No impact on optics (PDS)
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DIFFUSION OF PHOSPHORUS

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Doping mechanism and application in cell

+0.3 % absolute