Effects of post thermal annealing on the electrical properties of vertical type organic thin film transistors using poly(3-hexylthiophene) and its application in organic light emitting transistor.

We have fabricated the vertical type organic thin film transistor (OTFT) using electrically conductive poly(3-hexylthiophene) (P3HT) as a p-type organic material. Effects of post thermal annealing and thickness of active layer on the performance of vertical type transistors were investigated. Especially, the correlation between carrier mobility of P3HT after post thermal annealing and static characteristics of the transistor was studied. Carrier mobility was calculated by space charge limited current (SCLC) model from the I-V curves of the prepared device. The vertical type OTFT after post thermal annealing at 120 degrees C (Tg) showed high current of 0.383 mA and on-off ratio of 22.5 at a low gate voltage of +2.0 V. Additionally, we report on emission characteristics from the vertical type transistor using P3HT.