Stimulated emission in plasma-enhanced chemical vapour deposited silicon nanocrystals

✍ Scribed by L. Dal Negro; M. Cazzanelli; N. Daldosso; Z. Gaburro; L. Pavesi; F. Priolo; D. Pacifici; G. Franzò; F. Iacona

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 324 KB
• Volume: 16
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(02)00605-7

✦ Synopsis

Observation of optical gain in silicon nanocrystals (Si-nc) is critically dependent on a very delicate balance among the Si-nc gain cross-sections, the optical mode losses and conÿnement factors of the waveguide structures, the Si-nc concentration and the strongly competing fast non-radiative Auger processes. Here we report on optical gain measurements by variable stripe length (VSL) method on a set of silicon nanocrystals formed by thermal annealing at 1250 • C of SiOx ÿlms with di erent silicon contents prepared by plasma-enhanced chemical vapour deposition. Time-resolved VSL has revealed fast component in the recombination dynamics under gain conditions. Fast lifetime narrowing and superlinear emission has been unambiguously observed. To explain our experimental results we propose a four levels recombination model. Within a phenomenological rate equations description including Auger processes and ampliÿed spontaneous emission we obtained a satisfactory agreement with time-resolved experiments and explained the strong competition between stimulated emission and fast non-radiative Auger processes.