Organic metal-semiconductor field-effect phototransistors

We have prepared phototransistors based on bromine-doped pentacene. Such devices reveal light detection over a wide energy range with amplification. The illumination modifies the charge characteristics of the Schottky gate of an enhancement-mode the metal-semiconductor field-effect transistor leading to transistor amplification of the photodiode-like response. A gain of 8 is obtained for illumination at 632 nm. These phototransistors combine the excellent properties of pentacene field-effect transistors and photovoltaic devices. (C) 2001 American Institute of Physics.