Gas-sensitive characteristics of metal/semiconductor polymer Schottky device

Metal/polymer Schottky barrier diodes have been fabricated using electrochemically prepared films of polyaniline as the semiconductor and aluminium as the metal. Polyaniline was doped with HCl at room temperature to form a p-type semiconductor. On a sandwich-type device, the junction at Al/polyaniline showed rectifying behavior, and was used as a sensor for the detection of methane gas. The current–voltage (I–V) and capacitance–voltage (C–V) characteristics have been studied at room temperature, and the shifts in the I–V and C–V dependence of the diodes were measured with different concentrations of gas for different time intervals. The data have been analysed and interpreted on the basis of the thermionic emission mechanism.