Mixed self-assembled monolayer of molecules with dipolar and acceptor character—Influence on hysteresis and threshold voltage in organic thin-film transistors

Jedaa, Abdesselam; Salinas, Michael; Jäger, Christof M.; Clark, Timothy; Ebel, Alexander; Hirsch, Andreas; Halik, Marcus

doi:10.1063/1.3682301

Cited by 26 publications

(29 citation statements)

References 18 publications

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“…This results in considerable hysteresis in the voltage-current char-acteristics of the device. 13 When analyzing semiempirical molecular orbital calculations on such SAMs, 14 we noticed that the local electron affinity 15,16 indicated electron traps in the interstitial volumes between adjacent fullerenes in the semiconductor layer and that these traps were particularly deep when three fullerenes were involved. 14 A literature survey revealed that several groups have studied covalently linked fullerenes, their radical anions and dianions, [17][18][19][20][21][22][23][24][25][26][27][28][29][30] but that little attention has been paid to non-bonded van der Waals aggregates of fullerenes.…”

Section: Supporting Information Placeholdermentioning

confidence: 99%

Fullerene Van der Waals Oligomers as Electron Traps

et al. 2014

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Density functional theory calculations indicate that van der Waals fullerene dimers and larger oligomers can form interstitial electron traps in which the electrons are even more strongly bound than in isolated fullerene radical anions. The fullerenes behave like "super atoms", and the interstitial electron traps represent one-electron intermolecular σ-bonds. Spectroelectrochemical measurements on a bis-fullerene-substituted peptide provide experimental support. The proposed deep electron traps are relevant for all organic electronics applications in which non-covalently linked fullerenes in van der Waals contact with one another serve as n-type semiconductors.

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Section: Supporting Information Placeholdermentioning

confidence: 99%

Fullerene Van der Waals Oligomers as Electron Traps

et al. 2014

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“…Mixing different molecules with different diploes were a common method in the fabrication of memory devices as it combines the advantages of the two materials. Jedaa et al [62] reported a memory device based on three selfassembled materials with different functional groups: C 18 -PA, F 15 C 18 -PA, and C 60 -terminated octadecyl phosphonic acid on Al 2 O 3 substrate. Mixing these self-assembled molecules could effectively adjust the threshold voltage and hysteresis characteristics of the memory device.…”

Section: Surface Diploesmentioning

confidence: 99%

“…When enough negative bias voltage was applied in the gate electrode, the holes could be generated and the threshold voltage would be shifted to the negative direction. Jedaa et al [62] reported that mixing two or more kinds of self-assembly materials could effectively regulate the threshold voltage, suggesting that self-assembly technology was important to improve the performances of memory device. In 2010, Burkhardt et al [86] designed two self-assembly molecules: n-octadecylphosphonic acid and C 60 -derivative compound Reproduced with permission.…”

Section: Sam-aumentioning

confidence: 99%

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Interface Modification in Three‐Terminal Organic Memory and Synaptic Device

Zheng

Liao

Han

et al. 2020

Adv Elect Materials

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including floating-gate memory devices, [13] polymer memory devices, [14] and ferroelectric memory devices. [9] Generally, the structure of three-terminal organic memory devices is similar to the OFET except that a floating gate layer is added to the former between the semiconductor layer and the dielectric layer, through which the charges can be trapped or the polarization can be changed when the operation voltage is applied on the electrodes. Subsequently it leads to threshold voltage shift. It is reported that the electrical properties of OFET can be improved by modifying the interface between semiconductor layer and dielectric layer [15-17] since the charge transport is correlated to the interfaces. In view of this, interface engineering is in high demand to obtain excellent electrical characteristics. For three-terminal organic memory devices, the characteristics of the interface such as interfacial adhesion, [18] morphology, [19] surface diploes, energy level alignment, [20] hydrophilic/hydrophobic property [21] affect the charge transport of device. To control the interfacial property, some methods of interface modification are proposed which includes 1) inserting SAMs or polymer layer as the interfacial layer between dielectric layer and semiconductor layer and 2) pretreating the dielectric layer with ultraviolet-ozone (UVO), plasma, [22] or oxygen content technology. [23,24] Among these methods, SAMs are the most common and effective way to modify the interface because the interfacial properties such as morphology, hydrophilic/hydrophobic, and so on are adjustable by designing specific self-assembled molecules. [25] Nowadays, due to the physical separation of the memory unit from the central processor, the data shuttling between them consumes a large amount of energy with lower work efficiency, inducing memory wall effect. [26] Neuromorphic computing, by contrast, can break the "Von Neumann bottleneck" since these computers can simultaneously mimic the spatiotemporal learning and inference of the synapse in the human brain. [27] Three-terminal organic memory devices can be used to simulate excitatory post-synaptic current/potential (EPSC/ EPSP), synaptic weight, short-term plasticity (STP), long-term plasticity (LTP), and other functions of the artificial synapses, making artificial synapses a very popular research topic. [28,29] Similar to the mechanism of three-terminal organic memory devices, the properties of artificial synaptic devices based on three-terminal structure are also related to the interface between dielectric layer/semiconductor layer and source-drain Interface is a valuable research area for the three-terminal organic memory device, which is an important member of memory family, as the transport and trapping operation of charge carriers are related to the interfaces between semiconductor/dielectric layers and source-drain electrodes/semiconductor layer. This progress report highlights the developments of the interface effect for three-terminal organic memory devices. First, the goals of...

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“…While such methodology is useful for obtaining an overall picture of the graphene doping environment it makes it difficult to understand the exact relationship between SAMs and graphene. SAMs are commonly used in organic field‐effect transistors to modify the work function of metal electrodes, quench charge trap sites at the interface between semiconductor and metal or dielectric, and modulate the position of the threshold voltage . SAMs represent an ideal platform for control of graphene electronics as they can be designed and functionalized at the molecular scale to cater to specific device requirements.…”

Section: Introductionmentioning

confidence: 99%

Systematic Doping Control of CVD Graphene Transistors with Functionalized Aromatic Self‐Assembled Monolayers

Cernetic

Davies

et al. 2014

Adv Funct Materials

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3464www.MaterialsViews.com wileyonlinelibrary.com result in a linear dispersion for low energy carriers, which can be described as zero rest-mass relativistic particles with exemplary transport properties. [1][2][3] Electron mobility as high as 200 000 cm 2 V −1 s −1 can be achieved once extrinsic factors such as scattering centers from underlying substrates, adsorbates, and defects within graphene itself are controlled. [4][5][6][7][8][9] In order to utilize graphene for next generation electronic devices it is necessary to have precise control of carrier concentration and polarity without disrupting its intrinsic properties. Carrier doping of graphene has so far been achieved via chemical doping, [10][11][12][13] substitutional doping, [14][15][16] electric fi eld modulation, [ 17,18 ] and metal contact doping. [ 19,20 ] Recent reports have also shown it is possible to modulate the properties of graphene by modifying the underlying dielectric surface with a self-assembled monolayer (SAM) resulting in doping control without compromising the intrinsic graphene performance. [21][22][23][24] However, these studies use exfoliated graphene rather than the more commercially viable CVD-based graphene. In addition, exfoliation severely limits the ability to do a systematic and statistical study based on multiple devices due to the taxing processing steps necessary to fabricate individual devices. In order to circumvent this issue, characterization of these devices is mainly attributed to multiple Raman scans on a few pieces of modifi ed graphene rather than multiple pieces of graphene. While such methodology is useful for obtaining an overall picture of the graphene doping environment it makes it diffi cult to understand the exact relationship between SAMs and graphene. SAMs are commonly used in organic fi eld-effect transistors to modify the work function of metal electrodes, [ 25,26 ] quench charge trap sites at the interface between semiconductor and metal or dielectric, [27][28][29] and modulate the position of the threshold voltage. [30][31][32] SAMs represent an ideal platform for control of graphene electronics as they can be designed and functionalized at the molecular scale to cater to specifi c device requirements. However, there is still a need for better understanding of how SAM-treated dielectrics modulate the doping of graphene devices. In particular, an understanding of how the SAM dipole, while taking into account metal electrode effects, infl uences graphene has yet to be studied. In this paper we Recent reports have shown that self-assembled monolayers (SAMs) can induce doping effects in graphene transistors. However, a lack of understanding persists surrounding the quantitative relationship between SAM molecular design and its effects on graphene. In order to facilitate the fabrication of next-generation graphene-based devices it is important to reliably and predictably control the properties of graphene without negatively impacting its intrinsic high performance. In this study, SAMs with varying dipo...

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Mixed self-assembled monolayer of molecules with dipolar and acceptor character—Influence on hysteresis and threshold voltage in organic thin-film transistors

Cited by 26 publications

References 18 publications

Fullerene Van der Waals Oligomers as Electron Traps

Fullerene Van der Waals Oligomers as Electron Traps

Interface Modification in Three‐Terminal Organic Memory and Synaptic Device

Systematic Doping Control of CVD Graphene Transistors with Functionalized Aromatic Self‐Assembled Monolayers

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