Black silicon on emitter diminishes the lateral electric field and enhances the blue response of a solar cell by optimizing depletion region uniformity

A black silicon on emitter (BSOE) solar cell, with a uniform depletion region, was investigated by its internal quantum efficiency (IQE) and by scanning electron microscopy using an electron beam-induced current. We establish a three-dimensional energy band diagram of a non-uniform depletion region to illustrate the shunt effect by introducing a lateral electric field into the black silicon solar cell. The IQE spectral response at 450 nm is enhanced by ∼31%. The conversion efficiency is improved by 0.8%abs compared with a black silicon solar cell.