Optical gain has been recently observed in ion implanted Si nanocrystals (nc).(1) Critical issues to the observation of optical gain are the formation of a waveguide structure to improve the mode confinement and a large nanocrystal area density in the samples. Here we confirm these results by measuring optical gain by the variable stripe length (VSL) method on a set of silicon nanocrystals (nc) formed by plasma enhanced chemical vapor deposition (PECVD) and annealing treatments. Time resolved VSL measurements with ns pulses at high pumping fluencies have revealed fast component in the recombination dynamics under gain conditions. Lifetime shortening and superlinear emission have been unambiguously observed. The spectral shape of the fast luminescence is consistent with the amplified spontaneous emission lineshape (ASE) observed under CW pumping conditions and overlaps the gain spectral band. The observation of light amplification is critically dependent on a very delicate balance among the nc gain cross sections, the optical mode losses of the waveguide structure, and the fast non radiative Auger processes. Within a four levels model we quantify the strong competition among all these processes and we obtain a satisfactory agreement with the experiments.

Optical gain in PECVD grown silicon nanocrystals

Priolo F;Iacona F
2002

Abstract

Optical gain has been recently observed in ion implanted Si nanocrystals (nc).(1) Critical issues to the observation of optical gain are the formation of a waveguide structure to improve the mode confinement and a large nanocrystal area density in the samples. Here we confirm these results by measuring optical gain by the variable stripe length (VSL) method on a set of silicon nanocrystals (nc) formed by plasma enhanced chemical vapor deposition (PECVD) and annealing treatments. Time resolved VSL measurements with ns pulses at high pumping fluencies have revealed fast component in the recombination dynamics under gain conditions. Lifetime shortening and superlinear emission have been unambiguously observed. The spectral shape of the fast luminescence is consistent with the amplified spontaneous emission lineshape (ASE) observed under CW pumping conditions and overlaps the gain spectral band. The observation of light amplification is critically dependent on a very delicate balance among the nc gain cross sections, the optical mode losses of the waveguide structure, and the fast non radiative Auger processes. Within a four levels model we quantify the strong competition among all these processes and we obtain a satisfactory agreement with the experiments.
2002
Istituto per la Microelettronica e Microsistemi - IMM
0-8194-4576-2
silicon nanocrystals
optical gain
stimulated emission
light amplification
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/247356
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 1
social impact