Photoelectrochemical behavior of planar and microwire-array Si | GaP electrodes

Nicholas C. Strandwitz, Daniel B. Turner-Evans, Adele C. Tamboli, Christopher T. Chen, Harry A. Atwater, Nathan S Lewis

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Gallium phosphide exhibits a short diffusion length relative to its optical absorption length, and is thus a candidate for use in wire array geometries that allow light absorption to be decoupled from minority carrier collection. Herein is reported the photoanodic performance of heteroepitaxially grown gallium phosphide on planar and microwire-array Si substrates. The n-GaP | n-Si heterojunction results in a favorable conduction band alignment for electron collection in the silicon. A conformal electrochemical contact to the outer GaP layer is produced using the ferrocenium/ferrocene (Fc + /Fc) redox couple in acetonitrile. Photovoltages of ̃ 750 mV under 1 sun illumination are observed and are attributed to the barrier formed at the (Fc + /Fc) | n-GaP junction. The short-circuit current densities of the composite microwire-arrays are similar to those observed using single-crystal n-GaP photoelectrodes. Spectral response measurements along with a fi nitedifference- time-domain optical model indicate that the minority carrier diffusion length in the GaP is ̃ 80 nm. Solid-state current-voltage measurements show that shunting occurs through thin GaP layers that are present near the base of the microwire-arrays. The results provide guidance for further studies of 3D multi-junction photoelectrochemical cells.

Original languageEnglish
Pages (from-to)1109-1116
Number of pages8
JournalAdvanced Energy Materials
Volume2
Issue number9
DOIs
Publication statusPublished - Sep 2012

Fingerprint

Gallium phosphide
Light absorption
Photoelectrochemical cells
Electrodes
Voltage measurement
Electric current measurement
Silicon
Conduction bands
Acetonitrile
Short circuit currents
Sun
Heterojunctions
Current density
Lighting
Single crystals
Wire
Geometry
Electrons
Composite materials
Substrates

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

Cite this

Strandwitz, N. C., Turner-Evans, D. B., Tamboli, A. C., Chen, C. T., Atwater, H. A., & Lewis, N. S. (2012). Photoelectrochemical behavior of planar and microwire-array Si | GaP electrodes. Advanced Energy Materials, 2(9), 1109-1116. https://doi.org/10.1002/aenm.201100728

Photoelectrochemical behavior of planar and microwire-array Si | GaP electrodes. / Strandwitz, Nicholas C.; Turner-Evans, Daniel B.; Tamboli, Adele C.; Chen, Christopher T.; Atwater, Harry A.; Lewis, Nathan S.

In: Advanced Energy Materials, Vol. 2, No. 9, 09.2012, p. 1109-1116.

Research output: Contribution to journalArticle

Strandwitz, NC, Turner-Evans, DB, Tamboli, AC, Chen, CT, Atwater, HA & Lewis, NS 2012, 'Photoelectrochemical behavior of planar and microwire-array Si | GaP electrodes', Advanced Energy Materials, vol. 2, no. 9, pp. 1109-1116. https://doi.org/10.1002/aenm.201100728
Strandwitz, Nicholas C. ; Turner-Evans, Daniel B. ; Tamboli, Adele C. ; Chen, Christopher T. ; Atwater, Harry A. ; Lewis, Nathan S. / Photoelectrochemical behavior of planar and microwire-array Si | GaP electrodes. In: Advanced Energy Materials. 2012 ; Vol. 2, No. 9. pp. 1109-1116.
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