title: Incorporation of a self-aligned selective emitter to realize highly efficient (12.8%) Si nanowire solar cells.
abstract: Formation of a selective emitter in crystalline silicon solar cells improves photovoltaic conversion efficiency by decoupling emitter regions for light absorption (moderately doped) and metallization (degenerately doped). However, use of a selective emitter in silicon nanowire (Si NW) solar cells is technologically challenging because of difficulties in forming robust Ohmic contacts that interface directly with the top-ends of nanowires. Here we describe a self-aligned selective emitter successfully integrated into an antireflective Si NW solar cell. By one-step metal-assisted chemical etching, NW arrays formed only at light-absorbing areas between top-metal grids while selectively retaining Ohmic contact regions underneath the metal grids. We observed a remarkable ∼40% enhancement in blue responses of internal quantum efficiency, corresponding to a conversion efficiency of 12.8% in comparison to the 8.05% of a conventional NW solar cell.
authors.affiliation: Department of Materials and Chemical Engineering, Hanyang University, Ansan, 426-791, Korea. jungho@hanyang.ac.kr.
authors.forename: Han-Don
authors.initials: HD
authors.lastname: Um
authors.forename: Kwang-Tae
authors.initials: KT
authors.lastname: Park
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Jung
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Li
authors.forename: Keya
authors.initials: K
authors.lastname: Zhou
authors.forename: Sang-Won
authors.initials: SW
authors.lastname: Jee
authors.forename: Jung-Ho
authors.initials: JH
authors.lastname: Lee