Highly-ordered vertical Si nanowire/nanowall decorated solar cells.

Highly-ordered vertical nanowire and nanowall arrays are studied on Si solar cell surface. The nanowall textured solar cell is found to be more effective in reducing the overall optical reflectance, resulting in higher short circuit current (Jsc = 24.9 mA/cm²) over nanowire structured (Jsc = 23.3 mA/cm²) and planar (Jsc = 17.5 mA/cm²) solar cells. The extracted energy conversion efficiency (η) from planar solar cell is 7.1%, while nanowire/nanowall cells show efficiency of 8.2% and 6.3%, respectively. If corrected with series resistance (Rs), nanowall solar cell exhibits the highest η of 9.8% in this experiment. A careful study of the series resistance from different types of the nanostructures is also presented.