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Spectrally Resolved Photoluminescence Imaging of ZnO Nanocrystals at Single-Particle Levels

DSpace at IIT Bombay

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Title Spectrally Resolved Photoluminescence Imaging of ZnO Nanocrystals at Single-Particle Levels
 
Creator LAYEK, A
DE, S
THORAT, R
CHOWDHURY, A
 
Subject QUANTUM DOTS
SEMICONDUCTOR NANOCRYSTALS
SURFACE
LUMINESCENCE
SPECTROSCOPY
EMISSION
OXYGEN
NANOSTRUCTURES
NANOPARTICLES
TRANSITION
 
Description The intrinsic spectral line widths of defect-related transitions in quantum-confined semiconductor nanocrystals are often difficult to estimate using ensemble measurements because the extent of inhomogeneous broadening due to particle size distributions is not known precisely. To address this problem, we performed spectrally resolved photoluminescence (PL) microscopy of individual ZnO NC by directly populating the defects states using low-energy laser excitation. The temporal evolution of PL intensities shows discrete blinking behaviors, suggesting that the NCs are detected near single-particle levels. The transition energies of individual NCs are found to fluctuate around their mean position (2.25 eV) by similar to 0.130 eV, which is attributed to particle size distribution and defects densities associated with each NC. The spectral line width associated with defect emission envelope of ZnO NCs is found to be inherently broad (200-400 meV), which further establishes the presence of multiple closely spaced defect energy levels within every ZnO NC.
 
Publisher AMER CHEMICAL SOC
 
Date 2012-06-26T09:07:48Z
2012-06-26T09:07:48Z
2011
 
Type Article
 
Identifier JOURNAL OF PHYSICAL CHEMISTRY LETTERS,2(11)1241-1247
1948-7185
http://dx.doi.org/10.1021/jz200370s
http://dspace.library.iitb.ac.in/jspui/handle/100/14260
 
Language English