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Fırat M, Wouters L, Lagrain P, Haase F, Polzin JI, Chaudhary A, Nogay G, Desrues T, Krügener J, Peibst R, Tous L, Sivaramakrishnan Radhakrishnan H, Poortmans J. Local Enhancement of Dopant Diffusion from Polycrystalline Silicon Passivating Contacts. ACS Appl Mater Interfaces 2022; 14:17975-17986. [PMID: 35380425 DOI: 10.1021/acsami.2c01801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Passivating contacts consisting of heavily doped polycrystalline silicon (poly-Si) and ultrathin interfacial silicon oxide (SiOx) films enable the fabrication of high-efficiency Si solar cells. The electrical properties and working mechanism of such poly-Si passivating contacts depend on the distribution of dopants at their interface with the underlying Si substrate of solar cells. Therefore, this distribution, particularly in the vicinity of pinholes in the SiOx film, is investigated in this work. Technology computer-aided design (TCAD) simulations were performed to study the diffusion of dopants, both phosphorus (P) and boron (B), from the poly-Si film into the Si substrate during the annealing process typically applied to poly-Si passivating contacts. The simulated 2D doping profiles indicate enhanced diffusion under pinholes, yielding deeper semicircular regions of increased doping compared to regions far removed from the pinholes. Such regions with locally enhanced doping were also experimentally demonstrated using high-resolution (5-10 nm/pixel) scanning spreading resistance microscopy (SSRM) for the first time. The SSRM measurements were performed on a variety of poly-Si passivating contacts, fabricated using different approaches by multiple research institutes, and the regions of doping enhancement were detected on samples where the presence of pinholes had been reported in the related literature. These findings can contribute to a better understanding, more accurate modeling, and optimization of poly-Si passivating contacts, which are increasingly being introduced in the mass production of Si solar cells.
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Affiliation(s)
- Meriç Fırat
- Department of Electrical Engineering, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium
- Imec (Partner in EnergyVille), Kapeldreef 75, 3001 Leuven, Belgium
| | - Lennaert Wouters
- Imec (Partner in EnergyVille), Kapeldreef 75, 3001 Leuven, Belgium
| | - Pieter Lagrain
- Imec (Partner in EnergyVille), Kapeldreef 75, 3001 Leuven, Belgium
| | - Felix Haase
- ISFH, Am Ohrberg 1, 31860 Emmerthal, Germany
| | | | | | - Gizem Nogay
- CSEM, Rue Jacquet-Droz 1, 2002 Neuchâtel, Switzerland
| | - Thibaut Desrues
- Université Grenoble Alpes, CEA, LITEN, DTS, LPA, F-73370 Le Bourget-du-Lac, France
| | - Jan Krügener
- Leibniz University Hannover, Institute of Electronic Materials and Devices, Schneiderberg 32, 30167 Hannover, Germany
| | - Robby Peibst
- ISFH, Am Ohrberg 1, 31860 Emmerthal, Germany
- Leibniz University Hannover, Institute of Electronic Materials and Devices, Schneiderberg 32, 30167 Hannover, Germany
| | - Loic Tous
- Imec (Partner in EnergyVille), Kapeldreef 75, 3001 Leuven, Belgium
| | | | - Jef Poortmans
- Department of Electrical Engineering, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium
- Imec (Partner in EnergyVille), Kapeldreef 75, 3001 Leuven, Belgium
- Hasselt University, Campus Diepenbeek, Agoralaan Gebouw D, 3590 Diepenbeek, Belgium
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Van de Poel B, Bulens I, Lagrain P, Pollet J, Hertog MLATM, Lammertyn J, De Proft MP, Nicolaï BM, Geeraerd AH. Determination of S-adenosyl-l-methionine in fruits by capillary electrophoresis. Phytochem Anal 2010; 21:602-8. [PMID: 20690158 DOI: 10.1002/pca.1241] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
INTRODUCTION S-adenosyl-l-methionine (SAM) plays an important role in many biochemical reactions in plants. It is mainly used as a methyl donor for methylation reactions, but it also participates in, for example, the biosynthesis of polyamines and the plant hormone ethylene. OBJECTIVE To develop a fast capillary electrophoresis technique to separate SAM in fruits and fruit juices without any pre-purification steps. METHODOLOGY Four different extraction solutions and two extraction times were tested, of which 5% trichloroacetic acid (TCA) for 10 min was found most suited. A glycine : phosphate buffer (200 : 50 mm, pH 2.5) was found optimal to analyse SAM in TCA extracts. Analyses were preformed on different climacteric and non-climacteric fruits and fruit juices. The calibration curve was created in degraded tomato extract. The CE-method was compared with a more conventional HPLC method described in literature. RESULTS The CE technique made it possible to completely separate the S,S- and R,S-diastereoisomeric forms of SAM. The CE method proved to be very fast (20 min total running time instead of 42 min) and more sensitive (limit of detection of 0.5 µm instead of 1 µm) compared with the conventional HPLC method. CONCLUSION Fast measurements of SAM in fruits and juices are favoured by capillary electrophoresis in a 200 : 50 mm glycine : phosphate (pH 2.5) buffer system.
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Affiliation(s)
- Bram Van de Poel
- Department of Biosystems, Katholieke Universiteit Leuven, Willem de Croylaan 42, Leuven, Belgium.
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