High efficiency radial-junction Si nanohole solar cells formed by self-assembling high aspect ratio plasma etching

A drastic improvement in conversion efficiency was achieved from Si solar cells with radial-junction nanohole structure of a high aspect ratio of ~10 which is fabricated by self-assembling plasma etching. A conversion efficiency of 27.8 % was predicted based on an optimization of various structural parameters by numerical simulations, and a design principle for realizing high efficiency Si nanohole surface texture for photovoltaic devices was demonstrated.