Structural Modification of Organic Thin-Film Transistors for Photosensor Application
| Autor: | Hyeonju Lee, Jaehoon Park, Joel Ndikumana, Jin-Hyuk Bae, Hyeon Seok Jeong |
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| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Materials science business.industry Transistor General Physics and Astronomy Photodetector 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Capacitance Space charge law.invention Pentacene Organic semiconductor chemistry.chemical_compound chemistry Thin-film transistor law 0103 physical sciences Optoelectronics 0210 nano-technology business AND gate |
| Zdroj: | Journal of the Korean Physical Society. 72:1254-1263 |
| ISSN: | 1976-8524 0374-4884 |
| DOI: | 10.3938/jkps.72.1254 |
| Popis: | We investigated the light response characteristics of bottom-gate/top-contact organic TFTs fabricated using pentacene and polystyrene as an organic semiconductor and a polymeric insulator, respectively. The pentacene TFT with overlaps (50 μm) between the source and gate electrodes as well as between the drain and gate electrodes exhibited negligible hysteresis in its transfer characteristics upon reversal of the gate voltage sweep direction. When the TFTs were structurally modified to produce an underlap structure between the source and gate electrodes, clockwise hysteresis and a drain-current decrease were observed, which were further augmented by increasing the gate underlap (from 30 μm to 50 μm and 70 μm). Herein, these results are explained in terms of space charge formation and accumulation capacitance reduction. Importantly, we found that space charges formed under the source electrode contributed to the drain currents via light irradiation through the underlap region. Under constant bias conditions, the TFTs with gate underlap structures thus exhibited on-state drain current changes in response to light signals. In our study, an optimal photosensitivity exceeding 11 was achieved by the TFT with a 30 μm gate underlap. Consequently, we suggest that gate underlap structure modification is a viable means of implementing light responsiveness in organic TFTs. |
| Databáze: | OpenAIRE |
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