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Transactions on Electrical and Electronic Materials https://doi.org/10.1007/s42341-020-00246-4

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Effect of a Back‑Surface Field and Passivation Layer on a Silicon Schottky Solar Cell Djemaa Attafi1 · Rami Boumaraf1 · Amjad Meftah1 · Nouredine Sengouga1  Received: 25 March 2020 / Revised: 25 September 2020 / Accepted: 29 September 2020 © The Korean Institute of Electrical and Electronic Material Engineers 2020

Abstract In this work, a numerical simulation of a silicon based solar cell (SC) is carried out using Silvaco-Atlas software. The back contact and the back surface field (BSF) combined with a passivation layer (PL) realized by using ­SiO2 tunneling layer, is addressed in this paper. It is demonstrated that a proper choice of the BSF and PL can enhance a Schottky back contact based solar cell compared to its ohmic counterpart. BSF has to be properly doped to reduce the barrier of the Schottky contact. The tunnel oxide is a vital part in this solar cell. It is required to achieve excellent interface passivation and has to have an optimum thickness and below this thickness, the SC performance is enhanced by a tunneling effect, while it is deteriorated by the fill factor reduction above this optimum thickness. Keywords  Passivation · Back surface field · Tunneling effect · Numerical simulation

1 Introduction There are number of different semiconductor materials that are suitable for the conversion of photons energy into electrical energy; each of them has advantages and drawbacks. Among all materials, silicon is the most commonly used in solar cells manufacturing because it is very abundant on earth, nontoxic and it has an almost ideal band gap for photovoltaic solar energy conversion. For silicon-based solar cells, the theoretical limit conversion efficiency is ≈ 30%, in laboratory it is close to 25% while the commercial cells do not exceed 20% [1, 2]. n-type silicon based solar devices tend to have an excellent long-term stability of power conversion compared to their p-type counter parts [3, 4] because of better minority carrier lifetime [5]. Furthermore; these n-type Si solar are more tolerant to common transition metal doping impurities [6] and free of light induced degradation (LID) [7]. Recently, the passivation of solar cells surfaces became an additional step to improve their efficiency [8–10]. It used in photovoltaic cells in order to limit the defects created at the different stages of the cell manufacturing process, and to obtain high conversion efficiencies [11, 12]. In addition * Nouredine Sengouga n.sengouga@univ‑biskra.dz 1



LMSM, Mohammed Khider University, 07000 Biskra, Algeria

to passivation contact, polysilicon is used as a rear contact in solar cells, which provide a back field effect passivation with the chemical passivation of Si by SiOx , and eliminates the interface states on the tunneling layer/polysilicon interfaces that also may be accessible by tunneling recombination through the tunneling oxide [13, 14]. On the other hand, the use of Schottky barrier solar cells pr