scholarly journals Impact of Hydrogen Bonds Limited Dipolar Disorder in High-k Polymer Gate Dielectric on Charge Carrier Transport in OFET

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 826
Author(s):  
Bartosz Paruzel ◽  
Jiří Pfleger ◽  
Jiří Brus ◽  
Miroslav Menšík ◽  
Francesco Piana ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Charge Carrier ◽  
Charge Transport ◽  
Density Of States ◽  
Dielectric Layer ◽  
Carrier Transport ◽  
Gate Dielectric ◽  
Field Effect Transistors ◽  
Semiconductor Layer ◽  
High K

The paper contributes to the characterization and understanding the mutual interactions of the polar polymer gate dielectric and organic semiconductor in organic field effect transistors (OFETs). It has been shown on the example of cyanoethylated polyvinylalcohol (CEPVA), the high-k dielectric containing strong polar side groups, that the conditions during dielectric layer solidification can significantly affect the charge transport in the semiconductor layer. In contrast to the previous literature we attributed the reduced mobility to the broader distribution of the semiconductor density of states (DOS) due to a significant dipolar disorder in the dielectric layer. The combination of infrared (IR), solid-state nuclear magnetic resonance (NMR) and broadband dielectric (BDS) spectroscopy confirmed the presence of a rigid hydrogen bonds network in the CEPVA polymer. The formation of such network limits the dipolar disorder in the dielectric layer and leads to a significantly narrowed distribution of the density of states (DOS) and, hence, to the higher charge carrier mobility in the OFET active channel made of 6,13-bis(triisopropylsilylethynyl)pentacene. The low temperature drying process of CEPVA dielectric results in the decreased energy disorder of transport states in the adjacent semiconductor layer, which is then similar as in OFETs equipped with the much less polar poly(4-vinylphenol) (PVP). Breaking hydrogen bonds at temperatures around 50 °C results in the gradual disintegration of the stabilizing network and deterioration of the charge transport due to a broader distribution of DOS.

scholarly journals Crossover from band-like to thermally activated charge transport in organic transistors due to strain-induced traps

2017 ◽  
Vol 114 (33) ◽  
pp. E6739-E6748 ◽  
Author(s):  
Yaochuan Mei ◽  
Peter J. Diemer ◽  
Muhammad R. Niazi ◽  
Rawad K. Hallani ◽  
Karol Jarolimek ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Charge Carrier ◽  
Charge Transport ◽  
Organic Semiconductor ◽  
High Performance ◽  
Carrier Transport ◽  
Field Effect Transistors ◽  
Charge Carrier Mobility ◽  
Semiconductor Layer ◽  
Wide Range

The temperature dependence of the charge-carrier mobility provides essential insight into the charge transport mechanisms in organic semiconductors. Such knowledge imparts critical understanding of the electrical properties of these materials, leading to better design of high-performance materials for consumer applications. Here, we present experimental results that suggest that the inhomogeneous strain induced in organic semiconductor layers by the mismatch between the coefficients of thermal expansion (CTE) of the consecutive device layers of field-effect transistors generates trapping states that localize charge carriers. We observe a universal scaling between the activation energy of the transistors and the interfacial thermal expansion mismatch, in which band-like transport is observed for similar CTEs, and activated transport otherwise. Our results provide evidence that a high-quality semiconductor layer is necessary, but not sufficient, to obtain efficient charge-carrier transport in devices, and underline the importance of holistic device design to achieve the intrinsic performance limits of a given organic semiconductor. We go on to show that insertion of an ultrathin CTE buffer layer mitigates this problem and can help achieve band-like transport on a wide range of substrate platforms.

scholarly journals Inkjet-Printed Top-Gate Thin-Film Transistors Based on InGaSnO Semiconductor Layer with Improved Etching Resistance

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 425 ◽  
Author(s):  
Siting Chen ◽  
Yuzhi Li ◽  
Yilong Lin ◽  
Penghui He ◽  
Teng Long ◽  
...  
Keyword(s):  
Thin Film ◽  
Metal Oxide ◽  
Dielectric Layer ◽  
Thin Film Transistors ◽  
Gate Dielectric ◽  
Acid Resistance ◽  
Semiconductor Layer ◽  
Sn Doping ◽  
First Time

Inkjet-printed top-gate metal oxide (MO) thin-film transistors (TFTs) with InGaSnO semiconductor layer and carbon-free aqueous gate dielectric ink are demonstrated. It is found that the InGaO semiconductor layer without Sn doping is seriously damaged after printing aqueous gate dielectric ink onto it. By doping Sn into InGaO, the acid resistance is enhanced. As a result, the printed InGaSnO semiconductor layer is almost not affected during printing the following gate dielectric layer. The TFTs based on the InGaSnO semiconductor layer exhibit higher mobility, less hysteresis, and better stability compared to those based on InGaO semiconductor layer. To the best of our knowledge, it is for the first time to investigate the interface chemical corrosivity of inkjet-printed MO-TFTs. It paves a way to overcome the solvent etching problems for the printed TFTs.

Effect of Film Morphology on Charge Transport in C60-based Organic Field Effect Transistors

2010 ◽  
Vol 1270 ◽  
Author(s):  
Mujeeb Ullah ◽  
Andrey K. Kadashchuk ◽  
Philipp Stadler ◽  
Alexander Kharchenko ◽  
Almantas Pivrikas ◽  
...  
Keyword(s):  
Grain Size ◽  
Charge Carrier ◽  
Substrate Temperature ◽  
Charge Transport ◽  
Field Effect ◽  
Carrier Mobility ◽  
Field Effect Transistors ◽  
Charge Carrier Mobility ◽  
Film Morphology ◽  
Organic Field Effect Transistors

AbstractThe critical factor that limits the efficiencies of organic electronic devices is the low charge carrier mobility which is attributed to disorder in organic films. In this work we study the effects of active film morphology on the charge transport in Organic Field Effect Transistors (OFETs). We fabricated the OFETs using different substrate temperature to grow different morphologies of C60 films by Hot Wall Epitaxy. Atomic Force Microscopy images and XRD results showed increasing grain size with increasing substrate temperature. An increase in field effect mobility was observed for different OFETs with increasing grain size in C60 films. The temperature dependence of charge carrier mobility in these devices followed the empirical relation named as Meyer-Neldel Rule and showed different activation energies for films with different degree of disorder. A shift in characteristic Meyer-Neldel energy was observed with changing C60 morphology which can be considered as an energetic disorder parameter.

Low voltage and high ON/OFF ratio field-effect transistors based on CVD MoS2 and ultra high-k gate dielectric PZT

Nanoscale ◽  
2015 ◽  
Vol 7 (19) ◽  
pp. 8695-8700 ◽  
Author(s):  
Changjian Zhou ◽  
Xinsheng Wang ◽  
Salahuddin Raju ◽  
Ziyuan Lin ◽  
Daniel Villaroman ◽  
...  
Keyword(s):  
Low Power ◽  
Field Effect ◽  
Gate Dielectric ◽  
Low Voltage ◽  
Field Effect Transistors ◽  
Power Device ◽  
Enhancement Mode ◽  
High K ◽  
High K Gate Dielectric

Ultra high-k dielectric enables low-voltage enhancement-mode MoS2 transistor with high ON/OFF ratio, leading to low-power device.

scholarly journals Improved charge carrier transport in ultrathin poly(3-hexylthiophene) films via solution aggregation

2016 ◽  
Vol 4 (48) ◽  
pp. 11488-11498 ◽  
Author(s):  
Lukasz Janasz ◽  
Dorota Chlebosz ◽  
Marzena Gradzka ◽  
Wojciech Zajaczkowski ◽  
Tomasz Marszalek ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Ultrathin Films ◽  
Field Effect ◽  
Carrier Transport ◽  
Field Effect Transistors ◽  
Charge Carrier Transport ◽  
Maximum Charge ◽  
Solution Aggregation

Field-effect transistors based on poly(3-hexylthiophene) (P3HT) ultrathin films exhibit maximum charge carrier mobilities of up to 0.1 cm2 V−1 s−1.

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