GROWTH AND INVESTIGATION OF Alq3 THIN FILMS

We report preparation and properties of hybrid bilayer Structures composed of the organic semiconductor, 8-hydroxy-quinoline aluminum (Alq3), p-type Si and indium tin oxide (ITO). Thin Alq3 films were thermally evaporated in vacuum while ITO thin films were magnetron Sputtered oil glass. Surface morphology of the prepared organic films was studied by atomic force microscopy (AFM) while their thickness was measured by DECTAC profilometer. Chemical compositions of the films were investigated by X-Ray photoelectron spectroscopy method (XPS). Current-voltage (I-U) dependencies of the heterostructures were measured in a wide temperature range (T = 200 divided by 400 K). Most of the heterostructures exhibited nonlinear I-U dependencies and clearly defined rectifying properties. The vertical carrier transport in the Alq3/Si heterostructures has been explained taking into account Schottky thermoionic emission and certain influence of space charge limited current at high forward bias values.