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Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 22, Iss. 9 — May. 5, 2014
  • pp: 11029–11034

Infrared photoresponse of GeSn/n-Ge heterojunctions grown by molecular beam epitaxy

Sangcheol Kim, Nupur Bhargava, Jay Gupta, Matthew Coppinger, and James Kolodzey  »View Author Affiliations

Optics Express, Vol. 22, Issue 9, pp. 11029-11034 (2014)

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Heterojunction devices of Ge1-xSnx / n-Ge were grown by solid source molecular beam epitaxy (MBE), and the mid-infrared (IR) photocurrent response was measured. With increasing Sn composition from 4% to 12%, the photocurrent spectra became red-shifted, suggesting that the bandgap of Ge1-xSnx alloys was lowered compared to pure Ge. At a temperature of 100 K, the wavelengths of peak photocurrent were shifted from 1.42 µm for pure Ge (0% Sn) to 2.0 µm for 12% Sn. The bias dependence of the device response showed that the optimum reverse bias was > 0.5 volts for saturated photocurrent. The responsivity of the Ge1-xSnx devices was estimated to be 0.17 A/W for 4% Sn. These results suggest that Ge1-xSnx photodetectors may have practical applications in the near/mid IR wavelength regime.

© 2014 Optical Society of America

OCIS Codes
(040.5160) Detectors : Photodetectors
(060.4510) Fiber optics and optical communications : Optical communications
(200.4650) Optics in computing : Optical interconnects

ToC Category:

Original Manuscript: November 29, 2013
Revised Manuscript: March 25, 2014
Manuscript Accepted: April 21, 2014
Published: May 1, 2014

Sangcheol Kim, Nupur Bhargava, Jay Gupta, Matthew Coppinger, and James Kolodzey, "Infrared photoresponse of GeSn/n-Ge heterojunctions grown by molecular beam epitaxy," Opt. Express 22, 11029-11034 (2014)

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