Temperature dependent current-voltage characteristics of iron-phthalocyanine thin films.
The current-voltage (I-V) characteristics of the crystalline alpha-phase iron phthalocyanine (FePc) thin films grown by molecular beam epitaxy have been investigated by using a planar geometry in which the metal electrodes are separated by 15 microm. By carrying out the room temperature I-V measurements on vacuum annealed (200 degrees C for 30 min under 10(-6) torr) FePc thin films under vacuum and after exposing them to the air, we demonstrate that the hysteresis in FePc films is intimately related to the filling and de-filling of surface traps created by chemisorbed oxygen. The presence of chemisorbed oxygen has been confirmed by the X-ray photoelectron spectroscopy. Room temperature I-V characteristics of air exposed films showed ohmic conduction in the lower voltage range and space-charge-limited-conductivity (SCLC) in the relatively high voltage. Temperature dependent measurements show that the hysteresis disappears at 250 K and the surface traps are distributed in energy about 0.22 eV deep.
Samanta
Soumen
S
Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Center Mumbai 400085, India.
Singh
Ajay
A
Debnath
A K
AK
Aswal
D K
DK
Gupta
S K
SK
Yakhmi
J V
JV
D004566:Electrodes; D007501:Iron; D056951:Photoelectron Spectroscopy; D013499:Surface Properties; D013696:Temperature
D007501:Iron