Pentacene phototransistor with gate voltage independent responsivity and sensitivity by small silver nanoparticles decoration

In this study, a Pentacene phototransistor (PT) decorated with silver nanoparticles (Ag-NPs) in bottom gate structure was demonstrated. With the ultra-small Ag-NPs, this device exploits surface plasmon resonance at 445 nm and established a stable surface conduction channel under light illumination. Therefore, the PT exhibit gate voltage independent responsivity and photosensitivity in broad range of gate voltage. The light-induced magnetized in ultra-small Ag-NPs that generate polarized surface electrons were used to explain the gate-voltage independent photocurrent. The maximum photosensitivity and responsivity are 2.1 × 10³ and 17.7 mA/W, respectively, under white-light illumination. They are enhanced around 25 times at gate voltage of 20 V than conventional phototransistor. This device may be used in flexible optical interactive display, white-light indoor communication, or optical sensors.