Effect of p-BaSi2 layer thickness on the solar cell performance of p-BaSi2/n-Si heterojunction solar cells

Abstract

B-doped p-BaSi2 epitaxial layers with a hole concentration of 2 × 1018 cm−3 were grown on n-Si substrates (resistivity ρ = 1–4 Ω cm) by molecular beam epitaxy to form p-BaSi2/n-Si heterojunction solar cells. We changed the p-BaSi2 layer thickness () from 10 to 50 nm and investigated its effect on solar cell performance. The open-circuit voltage almost saturated to be approximately 0.47 V at nm or higher. The short-circuit current density decreased when exceeded 20 nm. The fill factor reached a maximum of 0.60 at nm. The conversion efficiency η increased as increased, and reached a maximum of 9.9% at nm, and then decreased. On the basis of these results, the optimum was determined to be 20 nm in the present structure. The η value of 9.9% is the highest ever reported for semiconducting silicides.