Ultrafast dynamics of exciton formation in semiconductor nanowires
Journal
Small (Weinheim an der Bergstrasse, Germany)
Journal Volume
8
Journal Issue
11
Pages
1725
Date Issued
2012-06-11
Author(s)
Joyce, Hannah J
Lloyd-Hughes, James
Gao, Qiang
Tan, Hark Hoe
Jagadish, Chennupati
Johnston, Michael B
Herz, Laura M
Abstract
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.
Subjects
nanowires; photoluminescence; excitons; charge plasma; ultrafast spectroscopy; GAAS QUANTUM-WELLS; ELECTRON-HOLE PLASMAS; MOTT TRANSITION; INP NANOWIRES; RELAXATION; PHOTOLUMINESCENCE; RECOMBINATION; IONIZATION; ENERGY; GE
Publisher
WILEY-V C H VERLAG GMBH
Type
journal article