Radial junction solar cells prepared on single crystalline silicon wafers by metal‐assisted etching

Abstract

Radial junction solar cells have been proposed as an alternative device geometry to conventional planar solar cells with its remarkable electrical and optical performance. In this geometry, densely packed nano/micropillars allow minority carrier collection in the radial direction and shorten carrier diffusion length to p-n junction. Besides, reduced reflection from surface and increased light trapping in nano/ micropillars enhance solar cell efficiency. In this study, photolithography and metal-assisted etching (MAE) techniques are used to form well-ordered silicon micropillar arrays; standard doping, passivation, and metallization steps are followed to form radial junction solar cells. The effect of micropillar length on optical and electrical performance of the solar cells have been investigated. We observed that optical reflection from solar cells surface decreased with increasing micropillar length, hence solar cell short circuit current (J sc ) and efficiency (ɳ) increased. Our best solar cell efficiency is 15.6% and this is one of the highest reported values obtained from the radial junction solar cells prepared by MAE technique.