Fabrication of organic thin-film transistors by spray-deposition for low-cost, large-area electronics

2010 ◽  
Vol 11 (12) ◽  
pp. 1960-1965 ◽  
Author(s):  
Natalia A. Azarova ◽  
Jack W. Owen ◽  
Claire A. McLellan ◽  
Marsha A. Grimminger ◽  
Eric K. Chapman ◽  
...  
MRS Advances ◽  
2018 ◽  
Vol 3 (33) ◽  
pp. 1871-1876 ◽  
Author(s):  
Chen Jiang ◽  
Hanbin Ma ◽  
Arokia Nathan

Abstract:All-inkjet-printed organic thin-film transistors take advantage of low-cost fabrication and high compatibility to large-area manufacturing, making them potential candidates for flexible, wearable electronics. However, in real-world applications, device instability is an obstacle, and thus, understanding the factors that cause instability becomes compelling. In this work, all-inkjet-printed low-voltage organic thin-film transistors were fabricated and their stability was investigated. The devices demonstrate low operating voltage (<3 V), small subthreshold slope (128 mV/decade), good mobility (0.1 cm2 V−1 s−1), close-to-zero threshold voltage (−0.16 V), and high on/off ratio (>105). Several aspects of stability were investigated, including mechanical bending, shelf life, and bias stress. Based on these tests, we find that water molecule polarization in dielectrics is the main factor causing instability. Our study suggests use of a printable water-resistant dielectric for stability enhancement for the future development of all-inkjet-printed organic thin-film transistors.


2021 ◽  
Vol 16 (2) ◽  
pp. 1-11
Author(s):  
José Enrique Eirez Izquierdo ◽  
José Diogo da Silva Oliveira ◽  
Vinicius Augusto Machado Nogueira ◽  
Dennis Cabrera García ◽  
Marco Roberto Cavallari ◽  
...  

This work is focused on the bias stress (BS) effects in Organic Thin-Film Transistors (OTFTs) from poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT-C14) on both highly-doped Si and glass substrates. While the former had a thermally-grown SiO2 dielectric, the latter demanded an alternative dielectric that should be capable to withstand bottom contact lithography, as well as semiconducting thin-film deposition. In addition, it should represent one more step towards flexible electronics. In order to do that, poly(4-vinylphenol) (PVP) was blended to poly(melamine-co-formaldehyde) methylated (PMF). OTFTs on glass with a cross-linked polymer dielectric had a charge carrier mobility (μ) of 4.0x10-4 cm2/Vs, threshold voltage (VT) of 18 V, current modulation (ION/OFF) higher than 1x102, and subthreshold slope (SS) of -7.7 V/dec. A negative BS shifted VT towards negative values and produced an increase in ION/OFF. A positive BS, on the other hand, produced the opposite effect only for OTFTs on Si. This is believed to be due to a higher trapping at the PVP:PMF interface with PBTTT-C14. Modeling the device current along time by a stretched exponential provided shorter time constants of ca. 105 s and higher exponents of 0.7–0.9 for devices on glass. Due to the presence of increased BS effects, the application of organic TFTs based on PVP:PMF as flexible sensors will require compensating circuits, lower voltages or less measurements in time. Alternatively, BS effects could be reduced by a dielectric surface treatment.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Jack W. Owen ◽  
Natalia A. Azarova ◽  
Marsha A. Loth ◽  
Markos Paradinas ◽  
Mariona Coll ◽  
...  

The performance of organic thin-film transistors (OTFTs) is often strongly dependent on the fabrication procedure. In this study, we fabricate OTFTs of soluble small-molecule organic semiconductors by spray-deposition and explore the effect of processing parameters on film morphology and device mobility. In particular, we report on the effect of the nature of solvent, the pressure of the carrier gas used in deposition, and the spraying distance. We investigate the surface morphology using scanning force microscopy and show that the molecules pack along theπ-stacking direction, which is the preferred charge transport direction. Our results demonstrate that we can tune the field-effect mobility of spray-deposited devices two orders of magnitude, from 10−3 cm2/Vs to 10−1 cm2/Vs, by controlling fabrication parameters.


COSMOS ◽  
2009 ◽  
Vol 05 (01) ◽  
pp. 59-77
Author(s):  
YUNING LI ◽  
BENG S. ONG

Organic thin film transistors (OTFTs) are promising candidates as alternatives to silicon TFTs for applications where light weight, large area and flexibility are required. OTFTs have shown potential for cost effective fabrication using solution deposition techniques under mild conditions. However, two major issues must be addressed prior to the commercialization of OTFT-based electronics: (i) low charge mobilities and (ii) insufficient air stability. This article reviews recent progress in the design and development of thiophene-based polymer semiconductors as channel materials for OTFTs. To date, both high performance p-type and n-type thiophene-based polymers with benchmark charge carrier mobility of > 0.5 cm2 V-1 s-1 have been archived, which bring printed OTFTs one step closer to commercialization.


MRS Bulletin ◽  
2006 ◽  
Vol 31 (6) ◽  
pp. 455-459 ◽  
Author(s):  
Sangyun Lee ◽  
Bonwon Koo ◽  
Jae-Geun Park ◽  
Hyunsik Moon ◽  
Jungseok Hahn ◽  
...  

AbstractOrganic thin-film transistors (OTFTs) are considered indispensable in applications requiring flexibility, large area, low processing temperature, and low cost. Key challenges to be addressed include developing solution-processable gate dielectric materials that form uniform films over large areas and exhibit excellent insulating properties, reducing contact resistance at interfaces between organic semiconductors and electrodes, and optimizing the patterning of organic semiconductors. High-performance pentacene-based OTFTs have been reported with polymeric gate dielectrics and indium tin oxide source/drain electrodes. Using such OTFT backplates, a 15-in. 1024 X 768 pixel full-color active-matrix liquid-crystal display (AMLCD) and a 4.5-in. 192 X64 pixel active-matrix organic light-emitting diode (AMOLED) have been fabricated.


2012 ◽  
Vol 1435 ◽  
Author(s):  
Robert Mueller ◽  
Steve Smout ◽  
Myriam Willegems ◽  
Jan Genoe ◽  
Paul Heremans

ABSTRACTShort channel organic thin film transistors in bottom-gate, bottom contact configuration use typically gold metallization for the source and drain contacts because this metal can easily be cleaned from photoresist residuals by oxygen plasma or ultraviolet-ozone and allows also surface modification by self-assembled monolayers (e.g. thiols). Alternative low-cost bottom contact metallization for high performance short-channel organic thin film transistors are scarce because of the incompatibility of the bottom contact material with the cleaning step. In this work a new process flow, involving a temporary thin aluminum protection layer, is presented. Short channel (3.4 μm) pentacene transistors with lithographical defined and thiol modified silver source/drain bottom contacts (25 nm thick, on a 2 nm titanium adhesion layer) prepared according to this process achieved a saturation mobility of 0.316 cm2/(V.s), and this at a metal cost below 1% of the standard 30 nm thick gold metallization.


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