Correlation of texture of Ag/ZnO back reflector and photocurrent in hydrogenated nanocrystalline silicon solar cells

Abstract

We studied the effect of Ag/ZnO back reflectors (BRs) with textured Ag and thin ZnO layers on hydrogenated nanocrystalline silicon (nc-Si:H) solar cell performance. We found that the photocurrent density increases with Ag texture when the surface root-mean-square (RMS) is smaller than 40nm. The best Ag texture for nc-Si:H cells has an RMS ∼40nm and lateral feature size ∼500nm. Increasing the surface roughness further results in increased light scattering, but no additional gain in the photocurrent density is observed. Using the optimized BRs, we achieved a short circuit current density over 30mA/cm2 in nc-Si:H solar cells.