Engineering the Schottky barrier heights in InGaAs metal-semiconductor- metal photodetectors

Walter A. Wohlmuth, Mohamed Arafa, Aaditya Mahajan, Patrick J. Fay, Ilesanmi Adesida

Research output: Contribution to journalConference articlepeer-review


An InGaAs metal-semiconductor-metal photodetector (MSMPD) that employs engineered Schottky barrier heights is proposed and demonstrated in this work. By engineering the barrier heights a significant decrease in dark current with no change in the responsivity or the bandwidth can be obtained in these devices in comparison to conventional MSMPDs. For MSMPDs with an electrode width and spacing of 2 micrometer, a photosensitive area of 2500 micrometer squared, and an applied bias of 5 V, dark currents of 1.42 nA, 381 pA, and 188 pA were obtained for the conventional Ti/Au, the conventional Pt/Ti/Pt/Au, and the engineered Pt/Ti/Pt/Au- Ti/Au MSMPDs, respectively. A Pt/Ti/Pt/Au-Ti/Au MSMPD with a 2 micrometer electrode width and spacing and a broad photosensitive area of 15625 micrometer squared exhibited a dark current density of 18.1 fA/micrometer squared which is lowest dark current density ever reported in literature for an InGaAs MSMPD. The responsivity and bandwidth of the conventional and the engineered MSMPDs was measured and was found to be virtually identical.

Original languageEnglish (US)
Pages (from-to)52-60
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Dec 1 1997
EventOptoelectronic Integrated Circuits - San Jose, CA, United States
Duration: Feb 12 1997Feb 12 1997


  • Indium gallium arsenide
  • MSM
  • Metal-semiconductor-metal
  • Photodetector
  • Photodiode

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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