Light Amplification Using Inverted Core/Shell Nanocrystals: Towards Lasing in the Single-Exciton Regime

• DOI: 10.1021/jp0483371
• Publication Date: 2004-07-22T09:34:31Z
• Authors: Sergei A. Ivanov; Jagjit Nanda; Andrei Piryatinski; Marc Achermann; Laurent P. Balet; Ilia V. Bezel; Polina O. Anikeeva; Sergei Tretiak; Victor I. Klimov
• Keywords: Auger effect; Amplified spontaneous emission

Size-controlled spectral tunability and chemical flexibility make semiconductor nanocrystals (NCs) attractive as nanoscale building blocks for color-selectable optical-gain media. The technological potential of NCs lasing materials is, however, significantly diminished by highly efficient nonradiative Auger recombination multiexcitons leading to ultrafast decay optical gain. Here we explore a novel approach achieve NC in the Auger-recombination-free regime using type II heterostructures that promote spatial separation electrons holes. We show such hetero-NCs can exhibit strong repulsive exciton−exciton interactions lead reduced excited-state absorption associated with containing single electron−hole pairs. This effect leads thresholds potentially allow single-exciton regime, which is inactive. use these demonstrate amplified spontaneous emission (ASE) tunable across "difficult" range green blue colors. ASE has never been previously achieved traditional I carrier localization.