p-BaSi2/n-Si heterojunction solar cells with 9.0% efficiency

Summary form only given. We fabricated p-BaSi
₂
/n-Si solar cells by forming a 20-nm-thick B-doped p-BaSi
₂
epitaxial layer (p = 2.2 × 10
¹⁸
cm
^-3
) on an n-Si(111) substrate (ρ = 1-4 Ω·cm) by molecular beam epitaxy (MBE). 3-nm-thick amorphous-Si was deposited on the p-BaSi
₂
surface to prevent the surface oxidation. According to the band alignment of p-BaSi
₂
/n-Si heterojunction, the separation of photogenerated minority carriers is promoted at the heterointerface. We recorded conversion efficiency of 9.0 % under AM1.5 illumination at room temperature. Short-circuit current density of 31.9 mA/cm
²
, open-circuit voltage of 0.46 V, and fill factor of 0.60 were obtained. These results suggest the potential of BaSi
₂
for solar cell application.