Photocarrier Generation in Fullerene Films

1994 ◽  
Vol 349 ◽  
Author(s):  
R. KÖnenkamp ◽  
J. Erxmeyer ◽  
A. Weidinger
Keyword(s):  
Sample Preparation ◽  
Charge Carriers ◽  
Electronic Transitions ◽  
Molecular Vibrations ◽  
Mobile Charge ◽  
Defect States ◽  
Molecular Electronic ◽  
Vibrational Bands ◽  
C60 Films

ABSTRACTWe present results from a detailed study of photoconductivity in thin C60 films. It is shown that the generation of mobile charge carriers involves molecular electronic transitions coupled to molecular vibrations. The vibrational bands broaden with temperature and shift at the fcc-to-scphase transition. For excitations with energy below ∼1.8 eV photoconduction appears to involve a tail of defect states whose distribution is somewhat dependent on sample preparation.

Experimental and modeling study of charge carriers release from traps by interaction with molecular vibrations in silicon organic polymers

2020 ◽  
Vol 697 (1) ◽  
pp. 68-84
Author(s):  
Volodymyr Sugakov ◽  
Nina Ostapenko ◽  
Yurij Ostapenko ◽  
Olga Kerita ◽  
Viktor Strelchuk ◽  
...  
Keyword(s):  
Charge Carriers ◽  
Molecular Vibrations ◽  
Organic Polymers ◽  
Modeling Study

Low temperature frequency dependence of the electron spin resonance absorption in heavily phosphorus-doped silicon

1970 ◽  
Vol 48 (24) ◽  
pp. 2930-2936 ◽  
Author(s):  
F. T. Hedgcock ◽  
T. W. Raudorf
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Magnetic Moments ◽  
Charge Carriers ◽  
Mobile Charge ◽  
Local Moments ◽  
Spin Resonance ◽  
Doped Silicon ◽  
Pauli Paramagnetism ◽  
Phosphorus Doped

Electron spin resonance (ESR) measurements have been made on a phosphorus-doped silicon specimen (n = 1.38 × 1019/cc) in the liquid helium temperature range. A single line with a g factor of approximately 2 was observed for resonant magnetic fields of 540, 3230, and 12 590 G at 1517, 9010, and 35 200 MHz respectively. The experimentally determined magnetization is compared with the magnetizations expected from the following sources: (a) un-ionized charge carriers or local magnetic moments obeying a Curie law, (b) mobile carriers experiencing an exchange interaction with local magnetic moments, and (c) mobile charge carriers showing only Pauli paramagnetism. The magnetization derived from the ESR data exhibits a linear dependence with magnetic field and no temperature dependence. This is consistent with the Pauli paramagnetism expected for mobile charge carriers in the absence of any interaction with local moments.

Long-Lived, Mobile Charge Carriers Formed on Photoexcitation of UV-Polymerized, Spin-Coated Films of Arylimido−Spacer−Diacetylene Derivatives

2000 ◽  
Vol 33 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Tom J. Savenije ◽  
John M. Warman ◽  
Helma M. Barentsen ◽  
Marinus van Dijk ◽  
Han Zuilhof ◽  
...  
Keyword(s):  
Charge Carriers ◽  
Mobile Charge

Structural transitions and electrical conductivity of C60 films at high temperature

1996 ◽  
Vol 11 (8) ◽  
pp. 2071-2075 ◽  
Author(s):  
Jinlong Gong ◽  
Guobin Ma ◽  
Guanghua Chen
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
Defect States ◽  
Order Of Magnitude ◽  
Fcc Phase ◽  
New Phase ◽  
C60 Films

X-ray diffraction analysis on C60 films shows that besides fcc phase, there also exists hcp phase, as well as a new crystalline phase with interplanar spacing (d-spacing) of planes parallel to the substrate 0.95 nm. The new phase may relate to the intercrystalline packed C60 molecules between fcc crystallites. The room temperature electrical conductivity of C60 films is found to be in the range of 10−5–10−8 (Ω · cm)−1. The room temperature conductivities of C60 films annealed at temperatures above 473 K are lower by one order of magnitude than those at temperatures below 463 K. This is because the interconnection between the fcc crystallites is weakened due to the disappearance of the new intercrystalline phase and the subsequent heightening of the intercrystalline potential barrier. From the measurement on the conductivity versus time when the film is maintained at a constant temperature, we identified the increase of conductivity is the result of the decrease of hcp phase, while the decrease of conductivity is due to the decrease of the new intercrystalline phase. Because the structures of the films become highly ordered, and defect states in the energy band gap decrease on annealing at high temperature, the conductivity activation energy increases.

A different view of molecular electronic transitions

1986 ◽  
Vol 90 (4) ◽  
pp. 580-583 ◽  
Author(s):  
Hugh Taylor ◽  
Jack Simons
Keyword(s):  
Electronic Transitions ◽  
Molecular Electronic
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