Molecular doping for control of gate bias stress in organic thin film transistors

Hein, Moritz; Zakhidov, Alex; Lüssem, Björn; Jankowski, Jens; Tietze, Max L.; Riede, Moritz; Leo, Karl

doi:10.1063/1.4861168

Cited by 40 publications

(44 citation statements)

References 29 publications

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“…Dopants present in the channel, originating from either diffusion or bulk doping of the semiconductor, create a prominent issue: while the free‐charge generation of channel dopants increases mobility, they often dramatically increase the off‐current, too. Despite these challenges, doping has been used to tune and improve nearly every aspect of OFET operation including mobility, charge trapping, threshold voltage, stability, and injection …”

Section: Reducing Contact Resistance: Electrode Design and Beyondmentioning

confidence: 99%

Contact Resistance in Organic Field‐Effect Transistors: Conquering the Barrier

Waldrip

Jurchescu

Gundlach

et al. 2019

Adv Funct Materials

226

261

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Organic semiconductors have sparked interest as flexible, solution processable, and chemically tunable electronic materials. Improvements in charge carrier mobility put organic semiconductors in a competitive position for incorporation in a variety of (opto-)electronic applications. One example is the organic field-effect transistor (OFET), which is the fundamental building block of many applications based on organic semiconductors. While the semiconductor performance improvements opened up the possibilities for applying organic materials as active components in fast switching electrical devices, the ability to make good electrical contact hinders further development of deployable electronics. Additionally, inefficient contacts represent serious bottlenecks in identifying new electronic materials by inhibiting access to their intrinsic properties or providing misleading information. Recent work focused on the relationships of contact resistance with device architecture, applied voltage, metal and dielectric interfaces, has led to a steady reduction in contact resistance in OFETs. While impressive progress was made, contact resistance is still above the limits necessary to drive devices at the speed required for many active electronic components. Here, the origins of contact resistance and recent improvement in organic transistors are presented, with emphasis on the electric field and geometric considerations of charge injection in OFETs.semiconductors with superior intrinsic charge transport properties, there is a stringent need to improve the device properties in order to allow organic devices to fulfill their technological prospectives. In the organic semiconductor community, contact resistance (R C ) has come under increased scrutiny as it is apparent that the final device performance is often domi nated by carrier injection, rather than the transport through the semiconductor layer. Contact resistance can impact OFET development in multiple ways. First, if not accounted for, a high contact resistance may lead to inaccurate extraction of the device parameters. Second, any inaccuracies in parameter extraction can have significant consequences on material development, from generating incorrect structure-property relationships to discarding organic semiconductors whose efficient intrinsic electrical properties have been masked by inefficient contacts. Beyond OFET and semiconductor characterization, analog, low power, and high frequency applications require a greater level of device parameter control than has been obtained in typical DC, high-voltage OFETs. For analog applications, e.g., integration of conditioning circuits such as local sense amps for distributed flexible sensor arrays, nonlinearity of the transistor response inhibits proper functioning and limits applicability of common models used to design circuitry. Low power device development for novel materials are hindered by the high voltage turn-on and current suppression in devices with large R C . Considering high-frequency applications, Klauk suggest...

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Section: Reducing Contact Resistance: Electrode Design and Beyondmentioning

confidence: 99%

Contact Resistance in Organic Field‐Effect Transistors: Conquering the Barrier

Waldrip

Jurchescu

Gundlach

et al. 2019

Adv Funct Materials

226

261

View full text Add to dashboard Cite

show abstract

Section: Recent Progress In Improving the Bias Stress Stability Of Ormentioning

confidence: 99%

“…Hein et al reported the enhancement of the bias stress stability of a p‐type semiconductor (pentacene) OFET via the slight doping of the channel with 2,2′‐(perfluoronaphthalene‐2,6‐diylidene)dimalononitrile (F6‐TCNNQ, p‐dopant) or tetrakis(1,3,4,6,7,8‐hexahydro‐2H‐pyrimido[1,2‐a]pyrimidinato)ditungsten (W2(hpp)4, n‐dopant) . Under constant bias stress, the I D decay was found to be significantly reduced as the p‐dopant concentration increases (Figure b,c): the time constant parameter, τ, extracted from Equation , increases from 605 s (0 wt%) to 6.73 × 10 5 s (1 wt%, F6‐TCNNQ) with increases in the p‐dopant concentration.…”

Section: Recent Progress In Improving the Bias Stress Stability Of Ormentioning

confidence: 99%

Recent Advances in the Bias Stress Stability of Organic Transistors

Park

Kim

Choi

et al. 2019

Adv Funct Materials

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In this progress report, recent advances in the development of organic transistors with superior bias stress stability and in the understanding of the charge traps that degrade device performance under prolonged bias stress are reviewed, with a particular focus on materials science and engineering methods. The phenomenological aspects of bias stress effects and the experimental methods for investigating charge traps are described. The recent progress in the bias stress stability of organic transistors is discussed in terms of those components that are the main focus of attempts to improve bias stress stability, i.e., organic semiconductor layers, gate dielectrics, and source/drain contacts. A brief summary of this progress is presented and the outlook for future research in this field is assessed. This report aims to summarize recent progress in this field and to provide some guidelines for studying bias stress-induced charge-trapping phenomena.

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“…For example, by doping separate charge transporting layers in organic solar cells and light emitting diodes charge selectivity can be ensured. Doping has also been utilized to deactivate traps in organic semiconductor devices and to reduce bias stress in organic transistors [10,11].…”

Section: Introductionmentioning

confidence: 99%