Optical properties of stacked Ge/Si quantum dots with different spacer thickness grown by chemical vapor deposition

Wen Yen Chen, Wen-Hao Chang, An Tai Chou, Tzu Min Hsu*, Pan Shiu Chen, Zingway Pei, Li Shyue Lai

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Photoluminescence spectroscopy has been used to study the optical properties of multiple stacked Ge/Si quantum dots (QDs) with different thickness of Si spacers inserted between the Ge dot layers. According to the emission energy of the stacked Ge/Si QDs, we found that thinner spacer will lead to significant material intermixing. Such intermixing degrades the interface sharpness and the hole confinement depth of the dots. The thermal activation energy of PL intensity quenching for different spacer thicknesses also confirms this finding. We point out that thinner spacer is in fact detrimental to the emission properties of the stacked Ge/Si QDs. To obtain better luminescence efficiency at room temperature, the influence of the material intermixing on stacked Ge/Si QDs should be minimized.

Original languageEnglish
Pages (from-to)148-151
Number of pages4
JournalApplied Surface Science
Volume224
Issue number1-4
DOIs
StatePublished - 15 Mar 2004

Keywords

  • Germanium
  • Material intermixing
  • QDs
  • Quantum dot
  • Strain relaxation

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