TY - JOUR
T1 - Photoinduced doping effect of pentacene field effect transistor in oxygen atmosphere studied by displacement current measurement
AU - Ogawa, Satoshi
AU - Naijo, Tatsuo
AU - Kimura, Yasuo
AU - Ishii, Hisao
AU - Niwano, Michio
N1 - Funding Information:
Part of this work was supported by Grants-in-Aid for Scientific Research (Nos. 15350075, 14205007, and 13640576) and Creative Scientific Research (No. 14GS0213) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.
PY - 2005
Y1 - 2005
N2 - It is widely accepted that atmospheric oxygen can work as an electron-accepting dopant mainly to p-type organic semiconductors. We have examined the effect of oxygen on a pentacene field effect transistor (FET) with and without exposure to light using the displacement current measurement. Under vacuum conditions, the change in the displacement current due to hole injection from the source and drain electrodes to the pentacene layer is clearly observed, suggesting that the origin of the mobile carriers in the pentacene FET is carrier injection. When the FET is exposed to oxygen under dark conditions, a very small change in the threshold gate voltage for hole injection is observed. In contrast, with exposure to both oxygen and light, we observed that the threshold voltage is lowered and shifted across the zero bias and even to the polarity against hole injection. This photoinduced doping effect induces a distinct increase in the drain current of the FET, and it is maintained for at least several hours even after the irradiation is turned off. This finding suggests that the performance of organic semiconductor devices is affected not only by atmospheric oxygen but also by ambient light even during the processing and storage of the devices.
AB - It is widely accepted that atmospheric oxygen can work as an electron-accepting dopant mainly to p-type organic semiconductors. We have examined the effect of oxygen on a pentacene field effect transistor (FET) with and without exposure to light using the displacement current measurement. Under vacuum conditions, the change in the displacement current due to hole injection from the source and drain electrodes to the pentacene layer is clearly observed, suggesting that the origin of the mobile carriers in the pentacene FET is carrier injection. When the FET is exposed to oxygen under dark conditions, a very small change in the threshold gate voltage for hole injection is observed. In contrast, with exposure to both oxygen and light, we observed that the threshold voltage is lowered and shifted across the zero bias and even to the polarity against hole injection. This photoinduced doping effect induces a distinct increase in the drain current of the FET, and it is maintained for at least several hours even after the irradiation is turned off. This finding suggests that the performance of organic semiconductor devices is affected not only by atmospheric oxygen but also by ambient light even during the processing and storage of the devices.
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U2 - 10.1063/1.1949281
DO - 10.1063/1.1949281
M3 - Article
AN - SCOPUS:24344488483
VL - 86
SP - 1
EP - 3
JO - Applied Physics Letters
JF - Applied Physics Letters
SN - 0003-6951
IS - 25
M1 - 252104
ER -