Tailoring the Electrical Properties of ZnO/Polyaniline Heterostructures for Device Applications

Jorlandio F. Felix, Eronides F. da Silva Jr, Elder A. de Vasconcelos and Walter M. de Azevedo

J. Korean Phys.Soc. 58,1256 [doi: 10.3938/jkps.58.1256 | PDF Download]

Low-cost nanostructured high-quality ZnO/Polyaniline heterostructure devices are produced by using the thermal evaporation and spin coating techniques. The devices present highly rectifying I-V characteristics, and under certain conditions, varistor characteristics are present with symmetric rectifying properties in both polarizations. The results indicate that by tuning the thickness of the ZnO thin film or the polymer doping state, the device뭩 electrical characteristics go from a standard diode (rectifying in forward polarization) to those of a varistor (rectifying in both forward and reverse polarizations). Further, only a device made with undoped polyaniline (PANI) may have its operation range tuned by adjusting properly the ZnO film뭩 thickness. The behavior observed is attributed to interfusion of ZnO-based composites, in the early stages of deposition, into the polymer chains and to the conducting islands surrounding the insulating sea in the PANI film. This gives rise to the formation of micron-sized Schottky contacts that electrically arrange themselves in a back-to-back configuration.