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Epitaxial III–V Films and Surfaces for Photoelectrocatalysis
Author(s) -
Döscher Henning,
Supplie Oliver,
May Matthias M.,
Sippel Philipp,
Heine Christian,
Muñoz Andrés G.,
Eichberger Rainer,
Lewerenz HansJoachim,
Hannappel Thomas
Publication year - 2012
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201200390
Subject(s) - epitaxy , heterojunction , optoelectronics , materials science , water splitting , tandem , nanotechnology , photocatalysis , chemistry , catalysis , biochemistry , layer (electronics) , composite material
Efficient photoelectrochemical devices for water splitting benefit from the highest material quality and dedicated surface preparation achieved by epitaxial growth. InP(100)‐based half‐cells show significant solar‐to‐hydrogen efficiencies, but require a bias due to insufficient voltage. Tandem absorber structures may provide both adequate potential and efficient utilization of the solar spectrum. We propose epitaxial dilute nitride GaPNAs photocathodes on Si(100) substrates to combine close‐to‐optimum limiting efficiency, lattice‐matched growth, and established surface preparation. Prior to a discussion of the challenging III–V/Si(100) heterojunction, we describe the closely related epitaxial preparation of InP(100) surfaces and its beneficial impact on photoelectrochemical water‐splitting performance. Analogies and specific differences to GaP(100) surfaces are discussed based on in situ reflectance anisotropy and on two‐photon photoemission results. Preliminary experiments regarding GaP/Si(100) photoelectrochemistry and dilute nitride GaPN heteroepitaxy on Si(100) confirm the potential of the GaPNAs/Si tandem absorber structure for future water‐splitting devices.