Compositional dependence of the absorption edge and dark currents in Ge1-x-ySixSny/Ge(100) photodetectors grown via ultra-low-temperature epitaxy of Ge4H10, Si 4H10, and SnD4

R. T. Beeler, Chi Xu, David Smith, G. Grzybowski, Jose Menendez, John Kouvetakis

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Lattice-matched Ge1-x-ySixSny (x ≤ 0.2, y ≤ 0.05) alloys were deposited defect-free on Ge(001) substrates via low-temperature (330-290 °C) reactions of Ge4H10, Si4H10 and SnD4 hydrides, and used to fabricate pin photodetectors. The growth is carried out under gas-source molecular beam epitaxy conditions in a specially designed single-wafer reactor. Optical responsivity measurements reveal absorption edges between 0.88 eV and 0.98 eV, which are used to determine the compositional dependence of the direct band gap. A study of the I-V characteristics of the diodes shows that the dark current is very weakly correlated with the number of Si-Sn bonds in the alloy.

Original languageEnglish (US)
Article number221111
JournalApplied Physics Letters
Issue number22
StatePublished - Nov 26 2012


ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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