Record infrared internal quantum efficiency in silicon heterojunction solar cells with dielectric/metal rear reflectors

Zachary Holman, Antoine Descoeudres, Stefaan De Wolf, Christophe Ballif

Research output: Contribution to journalArticle

73 Scopus citations


Inserting a dielectric between the absorber and rear metal electrode of a solar cell increases rear internal reflectance by both limiting the transmission cone and suppressing the plasmonic absorption of light arriving outside of the cone. We fabricate rear reflectors with low-refractive-index magnesium fluoride (MgF 2) as the dielectric, and with local electrical contacts through the MgF2 layer. These MgF2/metal reflectors are introduced into amorphous silicon/crystalline silicon heterojunction solar cells in place of the usual transparent conductive oxide/metal reflector. An MgF 2/Ag reflector yields an average rear internal reflectance of greater than 99.5% and an infrared internal quantum efficiency that exceeds that of the world-record UNSW PERL cell. An MgF 2/Al reflector performs nearly as well, enabling an efficiency of 21.3% and a short-circuit current density of nearly 38 mA/cm2 in a silicon heterojunction solar cell without silver or indium tin oxide at the rear.

Original languageEnglish (US)
Article number6587478
Pages (from-to)1243-1249
Number of pages7
JournalIEEE Journal of Photovoltaics
Issue number4
StatePublished - Sep 2 2013



  • Heterojunction
  • light trapping
  • magnesium fluoride
  • parasitic absorption
  • reflector
  • silicon
  • solar cell

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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