Photocurrent spectroscopy under depletion mode of transparent polymer field-effect transistors

The unique combination of voltage and light as the controlling parameters for charge transport in polymer-based field-effect transistors (PFETs) offers interesting strategies for light detection. Results of gate-voltage (Vg)-controlled intensity-modulated spectral response of the drain current in optically transparent PFETs are reported. The measurement and analysis of the results, obtained from light incident from the top and bottom side of the device, provide spatial information of the Vg-dependent photocarrier generation region. These measurements serve as a direct measure of the extent of the depletion.