Electrical characterization of controlled and unintentional modified metal–organic contacts

• Characterization of controlled and unintentional modified metal–organic contacts.
• Study of controlled technological treatments: SAMs, grafting with dipole molecules, doping, or forced degradation.
• Analysis of the relation free charge density at the metal–organic interface vs. current density.
• Evolution of the height of the interface energy barrier, impurities, traps with contact modifications.
• Initial clues after which more precise and costly experimental techniques can be employed for further analyses.

A method to characterize metal–organic contacts subjected to controlled technological treatments or unintentional degradation processes is proposed. The procedure is useful to characterize different fundamental aspects of a metal–organic structure such as the height of the interface energy barrier, the presence of impurities or trapping effects and the carrier mobility. Current–voltage curves in organic diodes are analyzed and the value of the free carrier density at the metal–organic interface is extracted and discussed. The charge carrier density is chosen for this analysis as this is one of the key physical parameters in the understanding of the physical processes involved in the device operation. The extracted charge, when described as a function of the current density, gives information about the doping and impurity concentration, the effective barrier seen by the carriers at the metal–organic interface or effective barriers seen by the carriers in the hopping processes across the organic material. An important advantage of the proposed procedure is the low computational time. Also, the procedure aims to provide a quick analysis for researchers on how the physical properties of the devices are evolving when they are technologically altered or degraded.

Figure optionsDownload as PowerPoint slide