GeSiSn photodiodes with 1 eV optical gaps grown on Si(100) and Ge(100) platforms

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29 Scopus citations


Ge 1-x-ySi xSn y alloys have reached a level of maturity that permits the creation of prototype devices on group-IV platforms. Here, we compare the optical and electrical properties of GeSiSn diodes with similar target compositions (Si; 10-11%, Sn; 1.7-2.3%) grown directly on Si(100) and Ge(100) using low erature ultrahigh vacuum chemical vapor deposition reactions of designer hydrides. The diodes grown on Ge substrates have relatively low ideality factors in the 1.3-1.4 range and low dark currents with a sizable diffusion component. The corresponding characteristics of the analogous devices grown on Si are significantly degraded due to mismatch-induced reduction in crystal quality. Quantum efficiency measurements show that both sets of diodes have absorption edges near 1eV with collection efficiencies reaching at least 76% in the devices grown on Ge. Collectively, these results suggest that Ge 1-x-y Si xSn y alloys represent a viable alternative as the long sought photovoltaic material with a lattice constant equal to that of Ge and a bandgap around 1eV.

Original languageEnglish (US)
Article number6244831
Pages (from-to)434-440
Number of pages7
JournalIEEE Journal of Photovoltaics
Issue number4
StatePublished - 2012


  • Photovoltaic cells
  • semiconductor diodes
  • semiconductor films
  • silicon compounds

ASJC Scopus subject areas

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


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