Polymer space-charge-limited transistor as a solid-state vacuum tube triode

Abstract

We report the construction of a polymer space-charge-limited transistor (SCLT), a solid-state version of vacuum tube triode. The SCLT achieves a high on/off ratio of 3×105 at a low operation voltage of 1.5 V by using high quality insulators both above and below the grid base electrode. Applying a greater bias to the base increases the barrier potential, and turns off the channel current, without introducing a large parasitic leakage current. Simulation result verifies the influence of base bias on channel potential distribution. The output current density is 1.7 mA/cm2 with current gain greater than 1000.

High-current operation of vertical-type organic transistor with preferentially oriented molecular film

“…The observed J DS was extremely high compared with those of other vertical-type organic transistors. [16][17][18][19][20][21][22][23][24][25][26] The gate current density (J G ) also increased with increasing V DS ; however, the observed J G was three orders of magnitude lower than J DS . Carriers cannot be injected in a gate electrode with increasing positive gate voltage unless the gate voltage exceeds the breakdown voltage.…”

“…Several groups have reported vertical-type organic transistors such as polymer grid transistors, organic a Email: fukagawa.h-fe@nhk.or.jp b Present address: Tokyo University of Science, Suwa, 5000-1 Toyohira, Chino-city, Nagano, 391-0292, Japan c Present address: Tohoku University, 6-6-05 Aramaki Aza Aoba, Aoba-ku, Sendai, 980-8579, Japan d Present address: Yamagata University, Research Center for Organic Electronics, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan static induction transistors (SITs), metal-base organic transistors (MBOTs), space-charge-limited transistors (SCLTs), patterned electrode vertical organic field effect transistor (PE-VOFET) and permeable-base transistor (PMBT) to realize a short channel. [15][16][17][18][19][20][21][22][23][24][25][26] However, the relationship between the crystalline axis of the organic film and the carrier transport direction has not been examined for vertical-type organic transistors. If the planar molecules are oriented with the molecular plane parallel to the substrate in a vertical-type organic transistor, the carrier transport direction can easily be aligned with the π-π stacking direction of the organic film.…”

“…5,9,10 In addition to planar OTFTs, vertical-type organic transistors have been reported in recent years. [15][16][17][18][19][20][21][22][23][24][25][26] The vertical structure is considered promising for attaining high-current and low-voltage operation, in which the carriers flow across the thin film in the vertical direction, perpendicular to the film plane, with short channel paths having lengths corresponding to the semiconductor film thickness. Several groups have reported vertical-type organic transistors such as polymer grid transistors, organic a Email: fukagawa.h-fe@nhk.or.jp b Present address: Tokyo University of Science, Suwa, 5000-1 Toyohira, Chino-city, Nagano, 391-0292, Japan c Present address: Tohoku University, 6-6-05 Aramaki Aza Aoba, Aoba-ku, Sendai, 980-8579, Japan d Present address: Yamagata University, Research Center for Organic Electronics, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan static induction transistors (SITs), metal-base organic transistors (MBOTs), space-charge-limited transistors (SCLTs), patterned electrode vertical organic field effect transistor (PE-VOFET) and permeable-base transistor (PMBT) to realize a short channel.…”

Vertical organic transistors withstanding high voltage bias

“…Well established device structure [16][17][18] was adopted to demonstrate this idea. This device geometry shown in Fig.…”

“…Various vertical organic transistors, such as triode-like transistors, hot-carrier transistors, and vertical field-effect transistors, have been developed with different device architectures and operating principles. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] These vertical transistors have been known for its high current driving capability without difficulty in making short channel, since the vertical channel length of a few hundred nanometers can be easily achieved by controlling the thickness of the organic layer deposited between the electrodes. A high on/off current ratio of 4 Â 10 4 has been demonstrated in a vertical organic transistor, called the polymer space-charge-limited transistor, operated at an extremely low operating voltage of 0.6 V. 20 The carrier holes are injected into the organic materials by the emitter electrode, passing through the openings on the base electrode, and finally being collected by the collector electrode.…”