The B ion implantation to BaSi2 films grown by molecular beam epitaxy was carried out to form p-type BaSi2 films. According to Raman spectra, post-annealing at over 600 °C for 64 min removed the ion-implantation damage. The hole concentration increased up to 3.1 × 1018 cm−3, which is applicable value to a hole transport layer. The B-ion-implanted p-BaSi2/n-Si heterojunction solar cells exhibited the rectifying behavior in current-voltage curves under AM1.5 illumination and the internal quantum efficiency reached a maximum of 72% at a wavelength of 900 nm. The conversion efficiency was 2.2%. These results open new routes for the formation methods of BaSi2 solar cells.
