title: Photoelectrochemical hydrogen evolution of tapered silicon nanowires.
abstract: The origin of the photocurrent enhancement and the overpotential reduction in solar water splitting employing nanostructured silicon is still a matter of debate. A set of tapered Si nanowires (SiNWs) has been designed for clarifying the impact of nanostructured Si on the hydrogen evolution reaction (HER) while precisely tailoring several interference factors such as surface area, light absorption and surface defect density. We find that defect passivation by KOH achieved by tapering is much more beneficial than the optical gain. Surfactant-mediated modification of SiNWs is capable of engineering the band structure. As a result, we suggest a guideline for nanostructured Si photoelectrodes optimized for the HER.
authors.affiliation: Max-Planck Institute of Microstructure Physics, Weinberg 2, Halle D-06120, Germany.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Li
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Xiao
authors.forename: Keya
authors.initials: K
authors.lastname: Zhou
authors.forename: Junna
authors.initials: J
authors.lastname: Wang
authors.forename: Stefan L
authors.initials: SL
authors.lastname: Schweizer
authors.forename: Alexander
authors.initials: A
authors.lastname: Sprafke
authors.forename: Jung-Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Ralf B
authors.initials: RB
authors.lastname: Wehrspohn