Estimation of electrical parameters of OD organic semiconductor diode from measured IN characteristics

In this paper the effect of temperature on the electrical properties of organic semiconductor disperse orange dye 25 (OD) have been examined. Thin films of OD have been deposited on In2O3 substrates using a centrifugal machine. DC current-voltage (I-V) characteristics of the fabricated devices (Al/OD/In2O3) have been evaluated at varying temperatures ranging from 40 to 60 degrees C. A rectification behavior in these devices has been observed such that the rectifying ratio increases as a function of temperature. I-V characteristics observed in Al/OD/In2O3 devices have been classified as low temperature (<= 50 degrees C) and high temperature characteristics (approximately 60 degrees C). Low temperature characteristics have been explained on the basis of the charge transport mechanism associated with free carriers available in OD, whereas high temperature characteristics have been explained on the basis of the trapped space-charge-limited current. Different electrical parameters such as traps factor, free carrier density, trapped carrier density, trap density of states, and effective mobility have been determined from the observed temperature dependent I-V characteristics. It has been shown that the traps factor, effective mobility, and free carrier density increase with increasing values of temperature, whilst no significant change has been observed in the trap density of states.