Unraveling Structure and Device Operation of Organic Permeable Base Transistors

Darbandy, Ghader; Dollinger, Felix; Hübner, René; Resch, Stefan; Roemer, Christian; Fischer, Axel; Leo, Karl; Kloes, Alexander; Kleemann, Hans

doi:10.1002/aelm.202000230

Cited by 11 publications

(11 citation statements)

References 22 publications

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“…The 15 nm thin aluminum base electrode is exposed to ambient air in the dark during the device fabrication, which creates a native AlO x insulating layer around the metal [19,20]. During the growth of the oxide layer, strain is induced into the Al film, leading to the formation of nanometer-sized openings [21] in the base electrode (pinholes). Therefore, these openings in the base electrode allow charge carriers from the emitter electrode to be transmitted through the base towards the collector electrode.…”

Section: Resultsmentioning

confidence: 99%

Reliable p-type organic permeable base transistors—the missing component for integrated circuits

Wang,

Bonil,

Vahland

et al. 2023

Nano Futures

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Due to their nm-range channel length, vertical organic transistors are gaining scientific interest to overcome the frequency limitations of lateral organic transistor. Especially, vertical organic permeable base transistors (OPBTs) with a structure resembling a vacuum-tube-triode stand out due to their excellentelectrical performance. Recently, n-type OPBTs have been demonstrated with excellent performance and great potential to be applied in high-frequency logiccircuits, display driving circuits, and light-emitting devices. However, achieving adequate p-type OPBTs to catch up with the performance of n-type devicesis still challenging. Here, we report on the peculiar finding that the extended exposure of p-type OPBTs to ambient air during the fabrication has a positive effect on the electrical performance and tremendously improves the yield of devices to 100%. Upon exposing the fresh device to air, oxygen diffuses intothe semiconductor layer interacting with the base electrode, which facilitates the formation of pinholes in the base and creates an insulator layer around thebase. Moreover, as oxygen acts as a p-dopants to the p-type semiconductors used in this work, the device performance is further improved, manifesting in anincreased on-state current. However, as the exposure time increases, different p-type organic semiconductors show different behavior depending on their ionization potential. Comparing two semiconductor materials with a difference in their ionization potential of 0.4 eV, we show that long-term degradation couldbe effectively suppressed.Therefore, the positive effect of air exposure could be utilized to optimize p-type OPBTs, which offers a simple and universal wayto construct high performance p-type OPBTs and possibly also complementary circuits.

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Section: Resultsmentioning

confidence: 99%

Reliable p-type organic permeable base transistors—the missing component for integrated circuits

Wang,

Bonil,

Vahland

et al. 2023

Nano Futures

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“…The models have been used with their default parameter values except for the calibrated parameters as shown in Supplementary Table 3 (refs. [45][46][47] ). The simulated DC characteristics (W = 250 μm and L = 250 μm) show a very good agreement between simulations (solid lines) and the experimental measurements (diamonds) (Fig.…”

Section: Resultsmentioning

confidence: 99%

Vertical organic permeable dual-base transistors for logic circuits

Guo

Darbandy

et al. 2020

Nat Commun

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The main advantage of organic transistors with dual gates/bases is that the threshold voltages can be set as a function of the applied second gate/base bias, which is crucial for the application in logic gates and integrated circuits. However, incorporating a dual gate/base structure into an ultra-short channel vertical architecture represents a substantial challenge. Here, we realize a device concept of vertical organic permeable dual-base transistors, where the dual base electrodes can be used to tune the threshold voltages and change the on-currents. The detailed operation mechanisms are investigated by calibrated TCAD simulations. Finally, power-efficient logic circuits, e.g. inverter, NAND/AND computation functions are demonstrated with one single device operating at supply voltages of <2.0 V. We believe that this work offers a compact and technologically simple hardware platform with excellent application potential for vertical-channel organic transistors in complex logic circuits.

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“…18 However, native oxidation of the base metal is broadly observed. 19 In this case, the overall electrical behavior of an OPBT can become quite close to that of a usual organic FET. 20 Therefore, the universal electrodes of an FET, i.e.…”

Section: Introductionmentioning

confidence: 82%