Passivation analysis of the Emitter and selective back surface field of silicon solar cells

Abstract

In this work the high-quality passivation of p-type Si solar cells with a boron-aluminum selective back surface field (BSF) and dry thermal SiO 2 layers on both surfaces is analyzed comparing the internal quantum efficiency (IQE) and the current-voltage parameters. This structure may be a viable substitute for the industry's standard solar cell, which has to be reconsidered when faced with the bowing problem. We observed that increasing oxidation temperature decreases IQE for short wavelengths (400 nm), while for long wavelengths (1000 nm) the IQE increases for temperatures lower than 860 • C. The same trend is observed for the solar cells' open circuit voltages, indicating that rear surface passivation increases for thicker oxides. The short-circuit current density was affected by the higher reflectance caused by the SiO 2 layer. However, by adjusting the TiO 2 anti-reflective coating thickness we were able to avoid this effect, achieving solar cells with efficiencies up to 16.8 %, which is comparable to the current efficiency of cells with Al-BSF covering the whole back surface. Furthermore, no bowing was observed for this structure.

Numerical analysis of dopant‐free asymmetric silicon heterostructure solar cell with SiO 2 as passivation layer

“…Furthermore, it is possible to passivate both p-and n-cSi wafers with SiO x making it a versatile film to be utilised for both back and front surfaces. 61 This permits a single oxidation step to passivate both sides of the wafer, which reduces fabrication cost. These fabricated results have demonstrated the applicability of MoO x and TiO x as hole-and electron-selective contacts for DASH solar cells.…”

“…Thermally grown SiO x provides low interface state density, 58 excellent interface passivation with cSi wafer, 59 impressive charge carrier tunnelling properties, 60 and stoichiometry close to SiO 2 59 that could be suitable for SHJ solar cell applications. Furthermore, it is possible to passivate both p‐ and n‐cSi wafers with SiO x making it a versatile film to be utilised for both back and front surfaces 61 . This permits a single oxidation step to passivate both sides of the wafer, which reduces fabrication cost.…”

Desenvolvimento Da Célula Solar Com Maior Eficiência No Brasil Com Processo Industrial

“…É possível realizar a passivação de ambas superfícies em uma única etapa térmica com o crescimento de dióxido de silício por meio de uma oxidação seca (Bonilla et al, 2017). Foi comprovado que este dielétrico pode ser eficaz na passivação de regiões altamente dopadas n + e p + (Razera et al, 2017), , (Chen et al, 2017). Porém, na oxidação térmica seca a taxa de crescimento é maior na região dopada com fósforo do que na região dopada com boro (Ho e Plummer, 1979).…”