| Summary: | 碩士 === 國立彰化師範大學 === 光電科技研究所 === 97 === In this study, we investigated the different surface treatments effects on the interface states of the pentacene-based thin-film transistor (TFT) with SiO2 as the gate insulator. We also extracted the interface states of the pentacene/SiO2 interface through conductance method.
In the first part, we investigated the improvement of electrical characteristics and interface states of pentacene/SiO2 interface with different surface treatments. The threshold voltage and off current of HMDS-treated OTFT would better than untreated OTFT, but the interface trap density has no significant change. The electrical characteristics and the interface states of pentacene/SiO2 interface of OTS-treated and PETS-treated OTFT would better than untreated OTFT. Thus, we observe significant change of the interface states properties of pentacene-based OTFT through surface treatments.
In the last part, we respectively investigated the electrical characteristics and interface states of pentacene-based TFT with SiO2 or PVP as the gate insulators in various measurement environments. The electrical characteristics become quite bad under illumination. The hysteresis of the C-V curve and interface trap density decrease under illumination. In 50°C, the electrical characteristics of the pentacene-based TFT with SiO2 gate insulator were found better than other temperature situations. The electrical characteristics and the hysteresis effect of the C-V curve become poor if the temperature is too high. In the same way, the electrical characteristics of the pentacene-based TFT with PVP gate insulator become poor under high temperature. When the temperature achieved 100°C, the hysteresis of the C-V curves met a reverse phenomenon from clockwise to counterclockwise.
In a short summary, the operation environments and structure components of pentacene TFTs seriously affect its electrical-optical properties. In this literature, there are still many mechanisms unclear and need more investigation.
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