CHARGE-TRANSPORT MECHANISM AND PHOTOVOLTAIC BEHAVIOR OF UNDOPED AND I-2 DOPED TRIS (1,10 PHENANTHROLINE) IRON (II) COMPLEX (TPFE) THIN-FILMDEVICES

Tris (1,10 phenanthroline) iron (II) or Fe (Phen)(3)(2+), a metal-to-l igand charge transfer (MLCT) type complex (TPFe), was employed in the form of thin films, for the fabrication of Schottky diodes, Al/TPFe/IT O, where ITO is indium tin oxide. The effect of iodine doping on the e lectrical behaviour has been emphasized. The diodes exhibit a rectific ation effect which improves on iodine doping. The diodes can be classi fied as MIS Schottky diodes with a graded dopant profile. The current- voltage (J-V), and capacitance-voltage (C-V) characteristics, the phot oaction spectra of the devices and the absorption spectra of the compl ex, reveal that both doped and undoped complexes behave as a p-type or ganic semiconductor which form a Schottky barrier with Al and an ohmic contact with ITO. Various electrical and photovoltaic parameters were determined from the detailed analysis of J-V and C-V characteristics and these are discussed in detail. The effect of I-2 doping on the rec tification and photovoltaic properties is also discussed. (C) 1998 Cha pman & Hall.