The mechanisms of photoluminescence from Si nanocrystals formed by pulsed-laser deposition

X. Y. Chen, Y. F. Lu, Y. H. Wu, B. J. Cho

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have investigated the different mechanisms of photoluminescence (PL) of Si nanocrystals (NCs) due to the quantum confinement effect (QCE) and interface states. Si NCs were formed by pulsed-laser deposition (PLD) in Ar or O 2 gas ambient. The collisions between the ejected species greatly influence the morphology of Si NCs and cause a transition from film structure to porous cauliflower-like structure, as the ambient gas pressure increases from 1 mTorr to 1 Torr. The optical absorption of the Si NCs shows an indirect band transition. Broad PL spectra are observed from Si NCs. The peak position and intensity of the PL band at 1.8-2.1 eV are dependent on excitation laser intensity, while intensity changes and blue shifts are observed after oxidation and thermal annealing. The PL band at 2.55 eV displays vibronic structures with periodic spacing of 97 ± 9 meV, while no peak shift is found before and after oxidation and thermal annealing. Combined with the PL of Si NCs obtained by crumbling electrochemical-etched porous Si layer, the results give strong evidence that the PL band at 1.8-2.1 eV is due to the QCE in Si NC core while the PL band at 2.55 eV is related to the localized surface states at SiO x/Si interfaces. Laser annealing of Si NC films was studied. Laser annealing improves the crystallinity and enhances the PL intensity, while high laser fluence causes damages in the films. After laser annealing, ripple structures consisting of nanoparticles are formed around the droplets on the film surface. The ripple period depends on the laser incident angle, which can be explained by the surface scattered wave theory.

Original languageEnglish (US)
Title of host publicationICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings
StatePublished - Dec 1 2003
EventICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics - Jacksonville, FL, United States
Duration: Oct 13 2003Oct 16 2003

Publication series

NameICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings

Conference

ConferenceICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics
CountryUnited States
CityJacksonville, FL
Period10/13/0310/16/03

Fingerprint

Pulsed laser deposition
Nanocrystals
Photoluminescence
laser
annealing
Annealing
Lasers
ripple
Quantum confinement
Gases
oxidation
Oxidation
Laser excitation
crystallinity
Interface states
gas
Surface states
surface wave
droplet
Surface waves

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Electrical and Electronic Engineering

Cite this

Chen, X. Y., Lu, Y. F., Wu, Y. H., & Cho, B. J. (2003). The mechanisms of photoluminescence from Si nanocrystals formed by pulsed-laser deposition. In ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings [M307] (ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings).

The mechanisms of photoluminescence from Si nanocrystals formed by pulsed-laser deposition. / Chen, X. Y.; Lu, Y. F.; Wu, Y. H.; Cho, B. J.

ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings. 2003. M307 (ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Chen, XY, Lu, YF, Wu, YH & Cho, BJ 2003, The mechanisms of photoluminescence from Si nanocrystals formed by pulsed-laser deposition. in ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings., M307, ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings, ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Jacksonville, FL, United States, 10/13/03.
Chen XY, Lu YF, Wu YH, Cho BJ. The mechanisms of photoluminescence from Si nanocrystals formed by pulsed-laser deposition. In ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings. 2003. M307. (ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings).
Chen, X. Y. ; Lu, Y. F. ; Wu, Y. H. ; Cho, B. J. / The mechanisms of photoluminescence from Si nanocrystals formed by pulsed-laser deposition. ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings. 2003. (ICALEO 2003 - 22nd International Congress on Applications of Laser and Electro-Optics, Congress Proceedings).
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