| Summary: | 博士 === 國立清華大學 === 電子工程研究所 === 99 === In this thesis, we have investigated the fundamental property of organic vertical-type triodes (OVTs) and their application. The OVTs are promising fabricated by employing two back-to-back Schottky diodes on the flexible or glass substrate. Due to the channel length depending on the thickness of active layer, the channel length can be controlled down to sub-micrometer and the device exhibits modulations with apparent saturation region while applying various supply voltages to the base electrode. To calculate effective mobility of the device, it is investigated by fitting the current-voltage characteristics at high voltages to the space-charge limited current (SCLC) model. The OVTs feature not only the operation procedures similar to those of bipolar junction transistors, but also those of planar-type organic thin-film transistors. Therefore, the first organic resistor-load inverter can also be achieved by integrating an OVT with a load resistor and their voltage transfer curves are demonstrated. To avoid the formation of the dipole at the metal/organic junction, a buffer layer of molybdic oxide (MoO3) is inserted at the metal/organic junction of OVT. The performance of devices featuring MoO3/Al as the emitter electrode is enhanced relative to that of corresponding devices with Au and Ag, presumably because of the reduced in the contact barrier and the prevention of metal diffusion into the organic layer. The device exhibited an output current of -16.1 μA at VB = -5 V and a current ON/OFF ratio of 103. To further realizing the complementary inverter, the similar performance of the p-channel OVT (ON current: -229 μA; OFF current: -67.6 nA; turn-on voltage: -0.8 V) and n-channel OVT (ON current: 377 μA; OFF current: 86.9 nA; turn-on voltage: 0.4 V) is fabricated and it exhibits a voltage gain of ca. 9 at a low supply voltage of 4 V. While the OVTs are operated under the current-driving mode, the OVTs operated at pronounced saturation with high gain by incorporating cascade-type energy band structure have been fabricated. Due to the most injection carriers can gain higher energy through the stepwise energy level, more carriers can surmount thin metal base electrode and diffused into the collector layer. Therefore, the device exhibited the transport factor of 0.99 and current gain of 20.93. Since the device exhibits the enough large current gain, a current mirror operated at out/in current ratio of 0.75 and output resistance of 105 Ω was achieved by integrating two p-channel OVTs with a load resistor. Theses application can enhance the development of the integrated circuits.
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