This thesis is based on the study of the electronic properties of Junction between Al andrnpoly[3-(2'-pentyloxy-5'-(1'''-oxoocty)phenyl)thiophene in the form of Al/poly[3-(2'-pentyloxy-rn5'-(1'''-oxoocty)phenyl)thiophene]/ITO sandwich structure. The junction between aluminiumrncontacts to poly[3-(2'-pentyloxy-5'-(1'''-oxoocty)phenyl]thiophene films was studied usingrncurrent-voltage, capacitance-voltage and complex impedance spectroscopy techniques. Therncurrent density-voltage curve is asymmetric and non-ohmic and shows Schottky barrier typernrectification. The complex impedance spectra are semi-circles that show the existence of arnregion depleted of mobile charge carriers. An equivalent circuit consisting of one parallel RCrncircuit is envisaged as a model of the interface