Development of High-Efficiency GaAs Solar Cells Grown on Nanopatterned GaAs Substrates

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11 Scopus Citations

Abstract

One approach to reducing the cost of high-efficiency III-V devices involves adding patterned layers to heteroepitaxial or homoepitaxial substrates to facilitate substrate removal and reuse. However, few studies have focused explicitly on high-quality devices grown over patterned substrates, which is required for any cost saving to be beneficial. In this work, we demonstrate the growth of high-efficiency GaAs solar cells on GaAs substrates patterned with an array of nanoscale SiOXmask stripes. We show that reducing the pattern dimensions to submicron length scales with nanoimprint lithography enables defect-free coalescence. By varying the growth conditions, faceting of the epilayer material during overgrowth of the patterned mask was also controlled. A V/III ratio of 200 during MOVPE overgrowth produced smooth coalesced epilayers, which is desirable for the growth of subsequent device layers. Inverted GaAs front homojunction devices grown on patterned GaAs(001) substrates achieved threading dislocation densities below 5 × 105cm-2and maintained >23% solar cell efficiencies at one sun illumination, equivalent to control devices grown on unpatterned epi-ready substrates.

Original languageAmerican English
Pages (from-to)5955-5960
Number of pages6
JournalCrystal Growth and Design
Volume21
Issue number10
DOIs
StatePublished - 6 Oct 2021

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society

NREL Publication Number

  • NREL/JA-5900-80586

Keywords

  • coalescence
  • GaAs
  • high-efficiency
  • III-V
  • patterned substrates
  • photovoltaic
  • PV

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