A conducting polymer–silicon heterojunction as a new ultraviolet photodetector

We discuss on the development and characterization of a p–n heterojunction of polyaniline–silicon as a photo detector for the ultraviolet (UV) region. The hybrid heterojunction consists of micro and nano-films (<300 nm thick) of polyaniline deposited on the top of a silicon wafer through the spin-coating technique, where in the backside of silicon and on top of polyaniline, aluminum and gold were respectively deposited by evaporation to make the electric contacts. The electrical characteristics of the devices present excellent reproducibility and high rectification ratio. In addition, the spectroscopic and the photon response analysis of the devices strongly indicates that it can be used as a broad band photon detector, with good sensitivity especially in the UV region ≈2.0–3.5 eV, where it presents enhanced sensitivity (≈200%) when compared to commercial all-silicon diodes such as the OPT 301 UV detector.