title: Temperature dependent current-voltage characteristics of iron-phthalocyanine thin films.
abstract: 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.
authors.affiliation: Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Center Mumbai 400085, India.
authors.forename: Soumen
authors.initials: S
authors.lastname: Samanta
authors.forename: Ajay
authors.initials: A
authors.lastname: Singh
authors.forename: A K
authors.initials: AK
authors.lastname: Debnath
authors.forename: D K
authors.initials: DK
authors.lastname: Aswal
authors.forename: S K
authors.initials: SK
authors.lastname: Gupta
authors.forename: J V
authors.initials: JV
authors.lastname: Yakhmi
mesh_terms: D004566:Electrodes; D007501:Iron; D056951:Photoelectron Spectroscopy; D013499:Surface Properties; D013696:Temperature
chemical_list: D007501:Iron