Ge nanocrystals formed by furnace annealing of Ge(x)[SiO2](1-x) films: Structure and optical properties

V. A. Volodin, A. G. Cherkov, A. Kh Antonenko, M. Stoffel, H. Rinnert, M. Vergnat

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Ge(x)[SiO2](1-x) (0.1 ≤ x ≤ 0.4) films were deposited onto Si(0 0 1) or fused quartz substrates using co-evaporation of both Ge and SiO2 in high vacuum. Germanium nanocrystals were synthesized in the SiO2 matrix by furnace annealing of Gex[SiO2](1-x) films with x ≥ 0.2. According to electron microscopy and Raman spectroscopy data, the average size of the nanocrystals depends weakly on the annealing temperature (700, 800, or 900 °C) and on the Ge concentration in the films. Neither amorphous Ge clusters nor Ge nanocrystals were observed in as-deposited and annealed Ge0.1[SiO2]0.9 films. Infrared absorption spectroscopy measurements show that the studied films do not contain a noticeable amount of GeOx clusters. After annealing at 900 °C intermixing of germanium and silicon atoms was still negligible thus preventing the formation of GeSi nanocrystals. For annealed samples, we report the observation of infrared photoluminescence at low temperatures, which can be explained by exciton recombination in Ge nanocrystals. Moreover, we report strong photoluminescence in the visible range at room temperature, which is certainly due to Ge-related defect-induced radiative transitions.

Original languageEnglish
Article number075010
Number of pages9
JournalMaterials Research Express
Volume4
Issue number7
DOIs
Publication statusPublished - 1 Jul 2017

Keywords

  • Defects
  • Ge nanocrystals
  • Nanoclusters
  • Photoluminescence
  • Raman scattering
  • photoluminescence
  • SILICON
  • SIZE
  • NANOSTRUCTURES
  • BAND-GAP
  • ELECTROLUMINESCENCE
  • RAMAN-SPECTROSCOPY DATA
  • INFRARED PHOTOLUMINESCENCE
  • NANOCLUSTERS
  • nanoclusters
  • defects
  • QUANTUM CONFINEMENT
  • EMISSION

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