Kerfless layer-transfer of thin epitaxial silicon foils using novel multiple layer porous silicon stacks with near 100% detachment yield and large minority carrier diffusion lengths

Radhakrishnan, Hariharsudan Sivaramakrishnan; Martini, Roberto; Depauw, Valérie; Nieuwenhuysen, Kris Van; Bearda, Twan; Gordon, Ivan; Szlufcik, Jozef; Poortmans, Jef

doi:10.1016/j.solmat.2014.10.049

Cited by 39 publications

(15 citation statements)

References 34 publications

(55 reference statements)

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“…We consider c-Si solar cells with Gaussian roughness for light trapping, focusing on the thickness dependence of the figures of merit and on the effect of extrinsic recombination. Our main goal is to understand realistic efficiency limits and prospects for thin-film c-Si solar cells produced with non-waferbased techniques like layer transfer or liquid-phase recrystallization [90][91][92][93][94][95], which are needed for thicknesses below the wafer limit of~80 µm.…”

Section: Electro-optical Modeling For Thin-film Silicon Solar Cellsmentioning

confidence: 99%

Silicon solar cells: toward the efficiency limits

Andreani

Bozzola

Kowalczewski

et al. 2018

Advances in Physics: X

279

211

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Photovoltaic (PV) conversion of solar energy starts to give an appreciable contribution to power generation in many countries, with more than 90% of the global PV market relying on solar cells based on crystalline silicon (c-Si). The current efficiency record of c-Si solar cells is 26.7%, against an intrinsic limit of~29%. Current research and production trends aim at increasing the efficiency, and reducing the cost, of industrial modules. In this paper, we review the main concepts and theoretical approaches that allow calculating the efficiency limits of c-Si solar cells as a function of silicon thickness. For a given material quality, the optimal thickness is determined by a trade-off between the competing needs of high optical absorption (requiring a thicker absorbing layer) and of efficient carrier collection (best achieved by a thin silicon layer). The efficiency limits can be calculated by solving the transport equations in the assumption of optimal (Lambertian) light trapping, which can be achieved by inserting proper photonic structures in the solar cell architecture. The effects of extrinsic (bulk and surface) recombinations on the conversion efficiency are discussed. We also show how the main conclusions and trends can be described using relatively simple analytic models. Prospects for overcoming the 29% limit by means of silicon/perovskite tandems are briefly discussed.

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Section: Electro-optical Modeling For Thin-film Silicon Solar Cellsmentioning

confidence: 99%

Silicon solar cells: toward the efficiency limits

Andreani

Bozzola

Kowalczewski

et al. 2018

Advances in Physics: X

279

211

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“…A micron-thick porous Si layer is formed at the top of the wafer by electrochemical porosification. Then, monocrystalline Si foils are epitaxially grown on top of the porosified wafers [14][15][16]. After epitaxy, the cell processing starts by first processing the front sides of the foils while the foils remain attached to their parent substrates.…”

Section: Introductionmentioning

confidence: 99%

Silicon heterojunction interdigitated back-contact solar cells bonded to glass with efficiency >21%

Bearda

Radhakrishnan

et al. 2017

Solar Energy Materials and Solar Cells

Self Cite

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Previously, IMEC proposed the i 2-module concept which allows to process silicon heterojunction interdigitated back-contact (SHJ-IBC) cells on thin (<50 µm) Si wafers at module level. This concept includes the bonding of the thin wafer early on to the module cover glass, which delivers mechanical support to the wafer and thus significantly improves the production yield. In this work, we test silicone and EVA bonding agents and prove them to be resistant to all rear side processes, including wet and plasma processes. Moreover, a lift-off process using a sacrificial SiOx layer has been developed for emitter patterning to replace conventional lithography. The optimized process steps are demonstrated by the fabrication of SHJ-IBC cells on 6-inch 190 µm-thick wafers. Efficiencies up to 22.6% have been achieved on reference freestanding wafers. Excellent Voc of 734 mv and Jsc of 40.8 mA/cm 2 lead to an efficiency of 21.7% on silicone-bonded cells, where the high Voc indicates the process compatibility of the bonding agent. The developments that enabled such achievements and the key factors that limit the device performance are discussed in this paper.

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“…The reason for developing a layer-transfer process for thin-film solar cells is that a thinner wafer thickness of the silicon solar cells corresponds to a greater reduction in the consumption of the silicon substrate and a greater increase in cell efficiencies 12 . These benefits have prompted many renewable energy research teams to study kerfless techniques 13,14 for producing silicon layers with thicknesses of tens of micrometers (<50 μm) with layer-transfer processing. When manufacturing solar cells, the two processes of ion-cut and epitaxial growth are ideally used as little as possible.…”

Section: Introductionmentioning

confidence: 99%

Annihilating Pores in the Desired Layer of a Porous Silicon Bilayer with Different Porosities for Layer Transfer

Chiang

Lee

2019

Sci Rep

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A silicon layer that is tens of micrometers thick on a handle substrate is desired for applications involving power devices, microelectromechanical systems (MEMS), highly efficient silicon solar cells (<50 µm), etc. In general, if the initial silicon layer obtained from the layer transfer process using the etch-stop or ion-cut techniques, which may provide very accurate thickness control, is too thin, then additional epitaxial growth is required to increase the thickness of the silicon layer. However, epitaxial growth under strict predeposition conditions is a time-consuming and expensive process. On the other hand, producing porous silicon via anodization in a hydrofluoric acid solution offers an efficient way to control the dimensions of the generated pores directly on the nano- or macroscale via the current density. When sintering the porous layer via high-temperature argon annealing, the porosity of the porous layer determines whether this porous layer can serve as a device layer or a separation layer. In addition, it is clearly easier to create a transferred layer ten of micrometers thick via anodization than by ion implantation and/or epitaxial deposition.

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Kerfless layer-transfer of thin epitaxial silicon foils using novel multiple layer porous silicon stacks with near 100% detachment yield and large minority carrier diffusion lengths

Cited by 39 publications

References 34 publications

Silicon solar cells: toward the efficiency limits

Silicon solar cells: toward the efficiency limits

Silicon heterojunction interdigitated back-contact solar cells bonded to glass with efficiency >21%

Annihilating Pores in the Desired Layer of a Porous Silicon Bilayer with Different Porosities for Layer Transfer

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