In Situ, Time-Resolved Normal Incidence Reflectance Spectroscopy of Polycrystalline Platinum Microelectrodes in Aqueous Electrolytes

2005 ◽  
Vol 109 (1) ◽  
pp. 36-39 ◽  
Author(s):  
Iosif Fromondi ◽  
Ping Shi ◽  
Atsushi Mineshige ◽  
Daniel A. Scherson
Keyword(s):  
Normal Incidence ◽  
Reflectance Spectroscopy ◽  
Aqueous Electrolytes ◽  
Time Resolved ◽  
Polycrystalline Platinum

Redox Dynamics of Pd Supported on CeO2–ZrO2 during Oxygen Storage/Release Cycles Analyzed by Time-Resolved in Situ Reflectance Spectroscopy

2018 ◽  
Vol 122 (49) ◽  
pp. 28173-28181 ◽  
Author(s):  
Hiroshi Yoshida ◽  
Riichiro Kakei ◽  
Ayumi Fujiwara ◽  
Yuki Uchida ◽  
Masato Machida
Keyword(s):  
Reflectance Spectroscopy ◽  
Oxygen Storage ◽  
Time Resolved ◽  
Redox Dynamics

Exciton dynamics in thick GaN MOVPE epilayers deposited on sapphire.

1997 ◽  
Vol 2 ◽  
Author(s):  
J. Allègre ◽  
P. Lefebvre ◽  
J. Camassel ◽  
B. Beaumont ◽  
Pierre Gibart
Keyword(s):  
Layer Thickness ◽  
Buffer Layers ◽  
Rate Equations ◽  
Time Resolved ◽  
Versus Layer ◽  
Level Model ◽  
Shallow Impurities ◽  
Aln Buffer ◽  
Time Resolved Photoluminescence

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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