SiGe quantum dots over Si pillars for visible to near-infrared broadband photodetection

Wei Ting Lai, Po Hsiang Liao, Andrew P. Homyk, Axel Scherer, Pei-Wen Li

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


We demonstrate a successful selective growth of Si0.3Ge 0.7 quantum dots (QDs) over array of p+-Si nanopillars using a low-pressure chemical vapor deposition technique, and hereafter realized high-performance QD broadband photodiodes for visible to near-infrared photodetection based on heterostructures of indium tin oxide/Si 0.3Ge0.7 QD/Si pillar. Thanks to effective hole confinement and thus a built-in electric field within the SiGe QD, high ratios of photocurrent to dark current of ~2200, 100, and 30, respectively, were measured on our SiGe QDs-based photodiodes under illumination of 9 mW/cm 2 at wavelength of 500-800, 1300, and 1500 nm. The QD photodiode exhibits a very low dark current density of 3.2 × 10-8 A/cm2 and a tunable power-dependent linearity by applied voltage through the competition of electron drift and carrier recombination processes.

Original languageEnglish
Article number6544564
Pages (from-to)1520-1523
Number of pages4
JournalIEEE Photonics Technology Letters
Issue number15
StatePublished - 5 Aug 2013


  • Broadband photodetector
  • Selective deposition
  • Si nanopillar
  • SiGe quantum dot

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