Method of Manufacturing a Silicon Photovoltaic Cell With an Additional Energy Level in the Band Gap

THE SERIES OF INVENTIONS ENTITLED ”METHOD OF MANUFACTURING A SILICON PHOTOVOLTAIC CELL WITH AN ADDITIONAL ENERGY LEVEL IN THE BAND GAP”

Patent. 442496, Patent. 442643 and Patent. 443344

The subject of the invention is a series of three patent applications relating to a method of manufacturing silicon photovoltaic cells with an additional energy level in the semiconductor’s band gap, made by ion implantation method based on silicon doped with boron, phosphorus, or antimony. The cell consists of a p-type silicon layer and an n-type silicon layer, as well as rear and front contact along with a surface passivation layer and an anti-reflective coating, where two processes were added to the fabrication process: doping by ion implantation and post-implantation annealing.
The idea behind the method is that a layer of n-type or p-type silicon, doped with various elements (boron, phosphorus, or antimony), with a certain resistivity ρ, is implanted with neon ions of a certain dose D and energy E, and then annealed isochronously. This allows the generation of an additional energy level in the semiconductor’s band gap, which has the effect of increasing the efficiency of the solar cell by allowing a multi-step transition of electrons from the valence band to the intermediate band and then to the conduction band. In this way, a multi-step mechanism for absorption of photons with energies below the width of the band gap is provided, resulting in increased solar photoconversion efficiency.

The benefit of the inventions, taking into account the current directions of development of silicon cell fabrication technology, involving the increasing use of ion implantation in the manufacturing process, is to reduce the cost of implementing the invention and to increase the cost-effectiveness of using silicon cells, by increasing their efficiency. The use of ion implantation technology makes it possible to generate additional energy levels in the semiconductor’s band gap, which translates into an increase in photo-conversion efficiency, and thus the profitability of using the developed solution.

One of the current methods of increasing the efficiency of PV cells is the introduction of additional energy levels in the semiconductor’s band gap (e.g., IBSC and IPV cells). The invention is part of this direction and is a consequence of years of research on identifying and developing a way to generate additional energy levels in silicon, which made it possible to produce a prototype of a high-efficiency PV cell. The use of ion-implantation technology provides higher efficiency and reduces costs, not only by increasing the precision of doping but also by shortening the individual steps of cell fabrication. In the research work carried out so far, it has been proven that there is such a configuration of ion implantation conditions, post-implantation annealing and parameters of the implanted material that allows the generation of additional energy levels in the silicon band gap with activation energies within the range of silicon’s band gap energy (ΔEG=1,12 eV) for photovoltaic applications. All this will make it possible to manufacture a silicon PV cell by ion implantation technique and conduct tests to determine its parameters, especially efficiency, which will revolutionize the PV market.

1. Rear contact,
2. p-type silicon layer – base,
3. The additional energy level in the band gap,
4. n-type silicon layer – emitter,
5. Surface passivation layer with anti-reflective coating,
6. Front contact,
7. Implanted neon ion beam,
8. Band gap,
9. Valence band,
10. Conduction band