Premium
Ultrafast Dynamics of Exciton Formation in Semiconductor Nanowires
Author(s) -
Yong Chaw Keong,
Joyce Hannah J.,
LloydHughes James,
Gao Qiang,
Tan Hark Hoe,
Jagadish Chennupati,
Johnston Michael B.,
Herz Laura M.
Publication year - 2012
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201200156
Subject(s) - exciton , femtosecond , charge carrier , nanowire , materials science , heterojunction , semiconductor , photoluminescence , biexciton , chemical physics , excitation , electron , population , spectroscopy , condensed matter physics , molecular physics , optoelectronics , chemistry , physics , optics , laser , demography , quantum mechanics , sociology
The dynamics of free electron–hole pairs and excitons in GaAs–AlGaAs–GaAs core–shell–skin nanowires is investigated using femtosecond transient photoluminescence spectroscopy at 10 K. Following nonresonant excitation, a bimolecular interconversion of the initially generated electron–hole plasma into an exciton population is observed. This conducting‐to‐insulating transition appears to occur gradually over electron–hole charge pair densities of 2–4 × 10 16 cm −3 . The smoothness of the Mott transition is attributed to the slow carrier‐cooling during the bimolecular interconversion of free charge carriers into excitons and to the presence of chemical‐potential fluctuations leading to inhomogeneous spectral characteristics. These results demonstrate that high‐quality nanowires are model systems for investigating fundamental scientific effects in 1D heterostructures.