Acidic texturing of multicrystalline silicon wafers

Marstein, Erik Stensrud; Solheim, H.J.; Wright, Daniel Nilsen; Holt, A.

doi:10.1109/pvsc.2005.1488381

Cited by 13 publications

(4 citation statements)

References 10 publications

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“…Recently, there has been a surge of interest in the photovoltaic community on 'black silicon' (black Si) solar cells. Silicon (Si) solar cell manufacturing is shifting from solar cells with a microtextured front surface (such as the alkaline pyramid texture on monocrystalline Si (c-Si) [10] (see figure 1(a)) or acidic isotropic texture on multicrystalline Si (mc-Si) [11] (see figure 1(b))) to black Si solar cells where the front surface is nanotextured and consists of nanowires (NWs) (see figures 1(c) and (d)). Black Si solar cells have recently demonstrated high efficiencies, including a 22.1%-efficient black Si solar cell in which the NWs are made using cryogenic reactive ion etching, and that utilizes interdigitated back contacts and aluminum oxide front surface passivation [12].…”

Section: Black Si Materials Propertiesmentioning

confidence: 99%

Nanostructured silicon via metal assisted catalyzed etch (MACE): chemistry fundamentals and pattern engineering

Toor

Miller²,

Davidson

et al. 2016

Nanotechnology

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There are a range of different methods to generate a nanostructured surface on silicon (Si) but the most cost effective and optically interesting is the metal assisted wet chemical etching (MACE) (Koynov et al 2006 Appl. Phys. Lett. 88 203107). MACE of Si is a controllable, room-temperature wet-chemical technique that uses a thin layer of metal to etch the surface of Si, leaving behind various nano- and micro-scale surface features or 'black silicon'. MACE-fabricated nanowires (NWs) provide improved antireflection and light trapping functionality (Toor et al 2016 Nanoscale 8 15448-66) compared with the traditional 'iso-texturing' (Campbell and Green 1987 J. Appl. Phys. 62 243-9). The resulting lower reflection and improved light trapping can lead to higher short circuit currents in NW solar cells (Toor et al 2011 Appl. Phys. Lett. 99 103501). In addition, NW cells can have higher fill factors and voltages than traditionally processed cells, thus leading to increased solar cell efficiencies (Cabrera et al 2013 IEEE J. Photovolt. 3 102-7). MACE NW processing also has synergy with next generation Si solar cell designs, such as thin epitaxial-Si and passivated emitter rear contact (Toor et al 2016 Nanoscale 8 15448-66). While several companies have begun manufacturing black Si, and many more are researching these techniques, much of the work has not been published in traditional journals and is publicly available only through conference proceedings and patent publications, which makes learning the field challenging. There have been three specialized review articles published recently on certain aspects of MACE or black Si, but do not present a full review that would benefit the industry (Liu et al 2014 Energy Environ. Sci. 7 3223-63; Yusufoglu et al 2015 IEEE J. Photovolt. 5 320-8; Huang et al 2011 Adv. Mater. 23 285-308). In this feature article, we review the chemistry of MACE and explore how changing parameters in the wet etch process effects the resulting texture on the Si surface. Then we review efforts to increase the uniformity and reproducibility of the MACE process, which is critical for commercializing the black Si technology.

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Section: Black Si Materials Propertiesmentioning

confidence: 99%

Nanostructured silicon via metal assisted catalyzed etch (MACE): chemistry fundamentals and pattern engineering

Toor

Miller²,

Davidson

et al. 2016

Nanotechnology

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“…We used a HF/HNO 3 solution with H 2 SO 4 instead of a HF/HNO 3 solution with CH 3 COOH. A HF/HNO 3 /H 2 SO 4 system for surface texturing has previously been reported [12][13][14][15]; however, cell performance has never been investigated. As far as we know, this paper is the first to consider the cell performance of the acid textured cells using the HF/HNO 3 /H 2 SO 4 system.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a New Acid Solution for Texturization of Multicrystalline Silicon Solar Cells

Watanabe

Abe

Haruyama

et al. 2013

International Journal of Photoenergy

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Surface texturing methods using an alkaline solution for monocrystalline Si (c-Si) solar cells have been widely accepted to improve cell performance. However, multicrystalline Si (mc-Si) cells are difficult to be texturized by alkaline etching, because the grains in the substrates are randomly oriented. In this study, we considered a HF/HNO3/H2SO4acid solution for texturing the mc-Si cells. We evaluated the morphology of the textured surfaces and the reflectance spectra from the surfaces. The deep dimple textured structures are formed on the surfaces for only 30 seconds of the acid texturing process. This behavior results from the effect of H2SO4in the solution. This process obtains up to 14.7% conversion efficiencies of the acid textured cells. These conversion efficiencies are up to 1.3 times larger than those of the mirror-etched cells.

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“…[3][4][5][6][7][8][9][10][11][12][13][14] It competes here with other wet chemical etching methods commonly used to produce pyramidal structures, such as alkaline KOH 15 or isotropic hydrofluoric/nitric/acetic acid (HNA) etching. 16 Cu-MACE shares many similarities with the related MACE techniques that use other metals. As is also common with silver MACE (Ag-MACE), the copper species can be introduced from salts either directly in the etching bath (1-step), [5][6][7][8][9][10][11][12]17 or beforehand through electroless deposition (2-step).…”

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confidence: 99%

Effect of Various Copper Salt Precursors on Metal-Assisted Chemical Etching of Silicon

Williams¹,

Kolhep²,

Zacharias³

2019

ECS J. Solid State Sci. Technol.

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Metal-assisted chemical etching (MACE) of Si with unstable metals like Cu can be described with reference to the oxidation effect of aqueous Cu2+ metal cations, in combination with the dissolution of Si species by HF. For 1-step MACE, salt precursors introduce possibly oxidizing additional anionic species, such as NO3− ions from Cu(NO3)2, that cannot be ignored when explaining MACE. This study for the first time unites Cu(NO3)2-MACE with isotropic hydrofluoric/nitric/acetic acid (HNA) Si etching, by purposely avoiding extra oxidants like H2O2, and contrasting the etching characteristics with etchants containing CuSO4, Cu(OAc)2, or CuCl2 precursors. A new model involving Cu2+-promoted autocatalysis of reactive nitrogen species (RNSs) is discussed, which explains the high etch rates, the NO3− anion concentration dependence, and the induction period specific to Cu(NO3)2 etchants. These results highlight the importance of Cu salt precursor selection when rationally designing new Cu-containing wet chemical etchants for key applications like MEMS and black silicon.

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Acidic texturing of multicrystalline silicon wafers

Cited by 13 publications

References 10 publications

Nanostructured silicon via metal assisted catalyzed etch (MACE): chemistry fundamentals and pattern engineering

Nanostructured silicon via metal assisted catalyzed etch (MACE): chemistry fundamentals and pattern engineering

Evaluation of a New Acid Solution for Texturization of Multicrystalline Silicon Solar Cells

Effect of Various Copper Salt Precursors on Metal-Assisted Chemical Etching of Silicon

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