High switching speed copper phthalocyanine thin film transistors with cut-off frequency up to 25Â kHz

The characteristics of high frequency and high speed are demonstrated in vertical structure organic thin film transistors (VOTFTs) fabricated by DC magnetron sputtering and vacuum evaporation. The saturated current-voltage characteristics can be determined by drain-source negative bias voltage. Responsive frequency of the device is as high as 20 kHz when rectangular wave dynamic signal is applied to the gate-source electrode, and switch characteristic time reaches the microsecond. The unsaturated current-voltage characteristics are observed when the drain-source bias voltage is positive. In the condition of VDS = 3 V and VGS = 0 V, the drain-source current IDS is 2.986 × 10−5 A, and the current density is 1.194 mA/cm2. Cut-off frequency fc is 25 kHz when a small sine wave dynamic signal is applied to the gate-source electrode. The volt-ampere characteristic of VOTFTs transfers from linear to nonlinear with increasing of drain-source bias voltage.