Investigation of a‐Si (N+)/c‐Si (P) hetero‐junction solar cell through AFORS‐HET simulation

In this paper, a TCO/a‐Si(N⁺)/a‐Si(i)/c‐Si(P)/Al‐BSF(P⁺) structure hetero‐junction (HJ) cell model is developed. With AFORS‐HET V3.0, we investigate the influence of amorphous silicon (a‐Si) emitter and amorphous silicon (a‐Si)/crystalline silicon (c‐Si) interface defects on the HJ cell performance. Through modulating a‐Si(N⁺) emitter doping concentration and band offset at a‐Si/c‐Si interface, a maximum width value of 103 nm inversion layer is observed in the c‐Si(P) side. For 1 Ω.cm c‐Si (P) substrate, emitter doping of over 1 × 10²⁰ cm^?3 is necessary for achieving a high‐efficiency a‐Si/c‐Si HJ cell. Furthermore, defects at a‐Si(N⁺)/c‐Si(P) interface severely affect the open circuit voltage (Voc) and short circuit current density (Jsc) of the cell. Meanwhile, simulation indicates that Voc is more sensitive to interface defect density (Dit) than Jsc. A thin a‐Si(i) layer between a‐Si(N⁺) and c‐Si(P) does induce great improvement in Voc of TCO/a‐Si(N⁺)/a‐Si(i)/c‐Si(P)/Al‐BSF(P⁺) cell. As a result, high cell efficiency of 22.27% is achieved for a‐Si(N⁺)/c‐Si(P) HJ Cell with optimized parameters. Copyright © 2010 John Wiley & Sons, Ltd.