Junction devices based on sulfonated polyaniline

Schottky diodes were fabricated using aluminum/neutralized-sulfonated-polyaniline (SPAN) junctions. I-V and C-V measurements were made, and the barrier height (Phi(B)) and the background concentration (N-B) were determined to be 0.8 V and 4x10(17)/cm(3), respectively. Using:these diodes as gate control: depletion-mode thin-film transistors were fabricated with a source and drain made of gold Ohmic contacts. The transistors were characterized by I-V measurements, and the carrier mobility determined from devices operating in the \V-G\>\V-DS\ "linear" regime was about 0.01 cm(2)/V s. This high value of mobility could be attributed to the spherulitic (partially ordered) structures observed in the SPAN thin films. Field-effect transistors were also fabricated on SPAN films deposited on an n-doped silicon substrate acting as the gate electrode with a thermally grown oxide layer. A reasonably high on/off ratio (similar to 4x10(3)) was measured in these devices. (C) 1998 American Institute of Physics.