BARC/PUB/10//0274

 
 

Bias and temperature dependent charge transport in high mobility cobalt- phthalocyanine thin films

 
     
 
Author(s)

Samanta, S.; Aswal, D. K.; Singh, A.; Debnath, A. K.; Kumar, M. S.; Hayakawa, Y.; Gupta, S. K.; Yakhmi, J. V.

ABSTRACT

The temperature dependent current-voltage (J-V) characteristics of highly-oriented cobalt phthalocyanine films (rocking-curve width=0.11°) deposited on (001) LaAlO3 substrates are investigated. In the temperature range 300-100 K, charge transport is governed by bulk-limited processes with a bias dependent crossover from Ohmic (J ~ V) to trap-free space-charge-limited conduction (J ~ V2). The mobility (µ) at 300 K has a value of ~ 7 cm2 V-1 s-1 and obeys Arrhenius-type    (ln µ ~ 1/T) behavior. However, at temperatures < 100 K, the charge transport is electrode-limited, which undergoes a bias dependent transition from Schottky      (ln J ~ V1/2) to multistep-tunneling (conductivity varying exponentially on the inverse of the square-root of electric field).

 
 
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