Conductance and polarisability of C60 films.
Thin films of C60 deposited in vacuum are studied using current-voltage (I-V) measurements and atomic force microscopy (AFM). In situ electrical measurements give an average resistivity of ca. 30 Mn cm for the as-deposited films at room temperature. The I-V dependences are found to correspond to ohmic behaviour but they have a hysteresis shape attributed to remnant polarisation due to the domain structure of the films. AFM images show a grainy surface morphology for the deposited C60. Temperature dependent measurements in the range 290-365 K provide evidence for a variable range hopping mechanism of conductance with an activation energy of 0.8-1.0 eV. With further temperature increase the C60 films restructure leading to an increase in grain size and a change of the electrical properties with I-V dependences showing Schottky barrier formation. The effect of oxygen on the conductance of the C60 films under their exposure to an ambient atmosphere is considered and discussed.
Popok
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Department of Physics, Göteborg University, 41296 Göteborg, Sweden.
Jönsson
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M
Campbell
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D000388:Air; D004553:Electric Conductivity; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D004583:Electrons; D037741:Fullerenes / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000379:methods*; D049329:Nanostructures; D036103:Nanotechnology / Q000379:methods*; D013499:Surface Properties; D013696:Temperature
D037741:Fullerenes; C069837:fullerene C60