Photothermal Deflection Spectroscopy In Zns Electroluminescent Thin Films

1986 ◽  
Author(s):  
J. Barkyoumb ◽  
R. W. Christy
1995 ◽  
Vol 61 (2) ◽  
pp. 159-161 ◽  
Author(s):  
S. K. So ◽  
M. H. Chan ◽  
L. M. Leung

1995 ◽  
Vol 61 (2) ◽  
pp. 159-161 ◽  
Author(s):  
S. K. So ◽  
M. H. Chan ◽  
L. M. Leung

1997 ◽  
Vol 467 ◽  
Author(s):  
E. Morgado ◽  
M. Rebelo da Silva ◽  
R. T. Henriques

ABSTRACTMetastable defects have been created by light exposure in thin films of a-Si:H. The samples have been characterized by Photothermal Deflection Spectroscopy, Electron Spin Resonance, dark- and photo-conductivity. The experimental results are consistent with numerical calculations with a recombination model involving band tails and one class of correlated dangling-bond states. The effects of light-soaking on the ligh intensity and defect density dependences of photoconductivity are reproduced by the calculations. The model allows to explain the experimental trends by changes in the electronic occupation of the gap states produced by light-induced defects.


2009 ◽  
Vol 1154 ◽  
Author(s):  
Marco Stella ◽  
Monica Beatriz Della Pirriera ◽  
Joaquim Puigdollers ◽  
Joan Bertomeu ◽  
Cristobal Voz ◽  
...  

AbstractIn this paper the optical absorption properties of n-type C60 and PTCDA, and p-type CuPc small molecule semiconductors are investigated by optical transmission and Photothermal Deflection Spectroscopy (PDS). The results show the usual absorption bands related to HOMO-LUMO transitions in the high absorption region of the transmission spectra. PDS measurements also evidences exponential absorption shoulders with different characteristic energies. In addition, broad bands in the low absorption level are observed for C60 and PTCDA thin-films. These bands have been attributed to contamination due to air exposure. In order to get deeper understanding of the degradation mechanisms single and co-evaporated thin-films have been characterized by PDS. The dependence of the optical coefficient on exposure to light and air have been studied and correlated to the structural properties of the films (as measured by X-Ray Diffraction Spectroscopy). The results show that CuPc and PTCDA are quite stable against light and air exposure, while C60 shows important changes in its absorption coefficient. The bulk heterojunctions show stability in agreement with what observed for single layers, since the absorption coefficient of CuPc:PTCDA is almost not altered after the degradation treatments, while CuPc:C60 shows changes for low energy values.


2003 ◽  
Vol 74 (1) ◽  
pp. 863-865 ◽  
Author(s):  
S. Ogawa ◽  
K. Mori ◽  
H. Natsuhara ◽  
T. Ohashi ◽  
R. Sakakiyama ◽  
...  

1983 ◽  
Vol 102 (3) ◽  
pp. 259-263 ◽  
Author(s):  
J.G. Mendoza-Alvarez ◽  
B.S.H. Royce ◽  
F. Sánchez-Sinencio ◽  
O. Zelaya-Angel ◽  
C. Menezes ◽  
...  

1992 ◽  
Vol 270 ◽  
Author(s):  
Andrew Skumanich

ABSTRACTThe optical absorption spectra for thin films of sublimed C60 and C70 are presented. Both transmission spectroscopy and photothermal deflection spectroscopy are used to obtain the spectrum over a wide energy range (0.4 to 6.2 eV) for the same film. The optical gap varies for the different fullerenes. The value for C60 is ∼ 1.6 eV and the corresponding transition appears to be optically forbidden given the weakness of the absorption. Structure is observed on the “gap edge” which can be attributed to vibronic transitions. The gap region can be described in terms used for amorphous semiconductors, having features such as an Urbach edge, and sub-gap defect absorption. The similarity suggests that the nature of fullerene thin films may be analogous to amorphous silicon and carbon films. These films have both a molecular and an amorphous semiconductor nature.


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