Continuous tuning of the threshold voltage of organic thin-film transistors by a chemically reactive interfacial layer

Etschmaier, Harald; Pacher, Peter; Lex, Alexandra; Trimmel, Gregor; Slugovc, Christian; Zojer, Egbert

doi:10.1007/s00339-008-4995-z

Cited by 15 publications

(11 citation statements)

References 20 publications

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“…The drawback of such approaches is, however, that a high “programming” voltage is needed to tune V Th . Another possibility to tune V Th is by insertion of self-assembled monolayers23,24 or chemically reactive thin layers 25,26. The latter have been shown to tune V Th by a local channel doping using acid groups that can be combined with de-doping reactions using bases.…”

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confidence: 99%

“…25,26 with photoacid generator polymers 27. The goal hereby is to use them as an interface-modification layer (see Figure 1a), whose properties can be patterned photochemically, because, in contrast to the molecules used previously25,26, the acid group is formed only upon illumination. This paves the way for a photolithographic patterning of the interfacial doping and, thus, for controlling which transistors in a circuit operate in depletion or in enhancement mode.…”

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confidence: 99%

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Tuning the Threshold Voltage in Organic Thin‐Film Transistors by Local Channel Doping Using Photoreactive Interfacial Layers

et al. 2010

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confidence: 99%

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confidence: 99%

Tuning the Threshold Voltage in Organic Thin‐Film Transistors by Local Channel Doping Using Photoreactive Interfacial Layers

et al. 2010

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“…This approach can be easily adopted into our design by controlling the thickness of the SWNT thin films to fine-tune the device operation. Furthermore, by introducing a reactive interfacial layer between the SiO 2 layer and the SWNT film in thin-film transistors, the threshold voltage can also be tuned for optimizing the device performance [24]. To take advantage of the entire voltage range, especially in the low-power range, these approaches will be explored and used in our future experiments to advance our understanding in SWNTbased logic gate devices and circuits.…”

Section: Resultsmentioning

confidence: 98%

Solution-Based Fabrication and Characterization of a Logic Gate Inverter Using Random Carbon Nanotube Networks

Duan

Holmes

Ellard

et al. 2013

IEEE Trans. Nanotechnology

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Semiconducting carbon nanotubes (CNTs) are considered as one of the most promising candidates to replace silicon in future nano-electronics. Single-walled carbon nanotubes (SWNTs) have been used as an active channel material in field-effect transistors (FETs). The nanotube-based circuits show great potential in future electronics and computer technology. Integrating SWNT FETs to form logic gates-the basic units of integrated circuits (ICs)-needs both p-and n-type SWNT FETs. However, without doping, annealing, or other special treatment, the as-obtained SWNT FETs are typically p-type. Here we report a SWNT-based logic device-a logic gate inverter (or a NOT gate)-using simple fabrication methods. The critical components of the inverter including a p-type SWNT FET and an n-type SWNT FET are fabricated using low-cost materials and an easy-to-control solutionbased process. The introduction of polyethylenimine (PEI), a polymer with high electron-donating ability, to the device successfully converts the p-type FET to an n-type device. The resulting devices are air-stable outside a vacuum or an inert environment. Electrical characterization of these devices demonstrates that both p-type and n-type FETs produce typical field effects and the resulting logic gate inverter exhibits satisfactory switching characteristics. We believe that the combination of the simple fabrication methods, easy conversion of the transistors, and satisfactory logic gate switching performance can influence fundamental research in nano-materials and practical applications of nano-electronics.Index Terms-Conversion, field-effect transistor (FET), logic gate, logic gate inverter, single-walled carbon nanotube (SWNTs).

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“…They allow the fabrication of chemo‐responsive OTFTs detecting the presence of bases like ammonia that compensate the acid doping 36, 40. They can also be used for a controlled chemical tuning of V th over more than 80 V in rr‐P3HT based OTFTs containing acidic SAM 41. Beyond that, some of us have recently used photo‐acid polymers as interface modification layers to control the growth of organic layers 4 and to photo chemically tune V th 11.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of surface proton transfer doping in pentacene based organic thin‐film transistors

Außerlechner

Gruber

Hetzel

et al. 2011

Physica Status Solidi (a)

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A number of studies show that chemical modification of the semiconductor-dielectric interface can be used to control the threshold voltage (V th ) of organic thin film transistors (OTFTs). A promising chemical functionality to achieve that are acidic groups, which -at the semiconductor-dielectric interfacehave been used to realize chemically responsive OTFTs and easy to fabricate inverter structures. Especially for pentacene based OTFTs, the underlying chemical and physical mechanisms behind the acid-induced V th shifts are not yet fully understood. Their clarification is the topic of the present paper. To distinguish between space-charge and dipole-induced effects, we study the impact of the thickness of the gate oxide on the device characteristics achieving maximum V th -shifts around 100 V. To elucidate the role of the acid, we compare the doping of pentacene by acidic interfacial layers with the impact of hydrochloric acid vapour and investigate the consequences of exposing devices to ammonia. Complementary experiments using 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) as active layer hint toward the central (6 and 13) carbon atoms being subject to the electrophilic attack by the acidic protons. They also prove that the observed V th shifts in pentacene devices are indeed a consequence of the interaction between the acidic groups and the active material. The experimental device characterization is supported by driftdiffusion based device modelling, by quantum chemically simulations, as well as by contact angle, atomic force microscopy (AFM) and X-ray reflectivity (XRR). The combination of the obtained results leads us to suggest proton transfer doping at the semiconductor-dielectric interface as the process responsible for the observed shift of V th .

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Continuous tuning of the threshold voltage of organic thin-film transistors by a chemically reactive interfacial layer

Cited by 15 publications

References 20 publications

Tuning the Threshold Voltage in Organic Thin‐Film Transistors by Local Channel Doping Using Photoreactive Interfacial Layers

Tuning the Threshold Voltage in Organic Thin‐Film Transistors by Local Channel Doping Using Photoreactive Interfacial Layers

Solution-Based Fabrication and Characterization of a Logic Gate Inverter Using Random Carbon Nanotube Networks

Mechanism of surface proton transfer doping in pentacene based organic thin‐film transistors

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