Time-resolved photoluminescence on the stimulated emission in polycrystalline ZnO nanoparticles

2009 ◽  
Vol 282 (4) ◽  
pp. 579-582 ◽  
Author(s):  
Xiaofang Wang ◽  
Pingbo Xie ◽  
Fuli Zhao ◽  
Yanmin Wang
2005 ◽  
Vol 87 (9) ◽  
pp. 093108 ◽  
Author(s):  
W. M. Kwok ◽  
A. B. Djurišić ◽  
Y. H. Leung ◽  
W. K. Chan ◽  
D. L. Phillips

1994 ◽  
Vol 37 (4-6) ◽  
pp. 1133-1136
Author(s):  
C.J. Stevens ◽  
R.A. Taylor ◽  
J.F. Ryan ◽  
M. Dabbicco ◽  
M. Ferrara ◽  
...  

2006 ◽  
Vol 963 ◽  
Author(s):  
Vitaliy Avrutin ◽  
Umit Ozgur ◽  
Natalia Izyumskaya ◽  
Serguei Chevtchenko ◽  
Jacob Leach ◽  
...  

ABSTRACTZnO nanorods were grown by catalyst-assisted vapor phase transport on Si(001), GaN(0001)/c-Al2O3, and bulk ZnO(0001) substrates. Morphology studies showed that ZnO nanorods grew mostly perpendicularly to the GaN substrate surface, whereas a more random directional distribution was found for nanorods on Si. Optical properties of fabricated nanorods were studied by steady-state photoluminescence and time-resolved photoluminescence. Stimulated emission was observed from ZnO nanorods on GaN substrates. Raman spectroscopy revealed biaxial strain in the nanorod samples grown on Si. Conductive atomic force microscopy was applied to study I-V spectra of individual nanorods.


Nanophotonics ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 127-134 ◽  
Author(s):  
Xiao-Fei Liu ◽  
Fuchuan Lei ◽  
Tie-Jun Wang ◽  
Gui-Lu Long ◽  
Chuan Wang

AbstractThe precise measurement of gain lifetime at a specific wavelength holds significant importance for understanding the properties of photonic devices and further improving their performances. Here, we show that the evolution of gains can be well characterized by measuring linewidth changes of an optical mode in a microresonator; this method cannot be achieved using time-resolved photoluminescence (PL) spectroscopy. We use an erbium-doped high-Q whispering-gallery microresonator to show the feasibility of this method. With the increase of time after the pump laser is turned off, the transmission spectrum of a probe signal exhibits transitions from a Lorentz peak to a dip; this indicates a decay of optical gains, and the corresponding lifetime is estimated to be 5.1 ms. Moreover, taper fiber coupling is used to increase the pump and collection efficiency. This method can be extended to other materials and nanostructures.


2004 ◽  
Vol 84 (17) ◽  
pp. 3223-3225 ◽  
Author(s):  
Ü. Özgür ◽  
A. Teke ◽  
C. Liu ◽  
S.-J. Cho ◽  
H. Morkoç ◽  
...  

1996 ◽  
Vol 449 ◽  
Author(s):  
A. Hangleiter ◽  
F. Scholz ◽  
V. Härle ◽  
J. S. Im ◽  
G. Frankowsky

ABSTRACTBoth spontaneous and stimulated emission processes are essential ingredients for constructing a laser from the nitrides. Based on our picosecond time-resolved photoluminescence studies we show that spontaneous radiative recombination is strongly influenced by excitonic effects, both in bulk GaN and in quantum wells. Particularly in quantum wells, localization of excitons plays an important role. We have studied the optical gain spectra in GaInN/GaN and GaN/AlGaN double heterostructures and quantum wells, grown by LP-MOVPE, using the stripe excitation method. Both room temperature and low temperature measurements were performed. Based on our results, we discuss the physical mechanism of optical gain in the nitrides as well as consequences for laser operation. We show that localization or, equivalently, the formation of quantum dot like structures, governs the optical gain mechanism in the nitrides.


2010 ◽  
Vol 107 (8) ◽  
pp. 084306 ◽  
Author(s):  
Noh Soo Han ◽  
Hyeong Seop Shim ◽  
Joo Hee Seo ◽  
Sun Young Kim ◽  
Seung Min Park ◽  
...  

Author(s):  
J. Allègre ◽  
P. Lefebvre ◽  
J. Camassel ◽  
B. Beaumont ◽  
Pierre Gibart

Time-resolved photoluminescence spectra have been recorded on three GaN epitaxial layers of thickness 2.5 μm, 7 μm and 16 μm, at various temperatures ranging from 8K to 300K. The layers were deposited by MOVPE on (0001) sapphire substrates with standard AlN buffer layers. To achieve good homogeneities, the growth was in-situ monitored by laser reflectometry. All GaN layers showed sharp excitonic peaks in cw PL and three excitonic contributions were seen by reflectivity. The recombination dynamics of excitons depends strongly upon the layer thickness. For the thinnest layer, exponential decays with τ ~ 35 ps have been measured for both XA and XB free excitons. For the thickest layer, the decay becomes biexponential with τ1 ~ 80 ps and τ2 ~ 250 ps. These values are preserved up to room temperature. By solving coupled rate equations in a four-level model, this evolution is interpreted in terms of the reduction of density of both shallow impurities and deep traps, versus layer thickness, roughly following a L−1 law.


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