Fluoropolymer coatings for improved carbon nanotube transistor device and circuit performance

Abstract

Articles you may be interested inHigh-performance carbon-nanotube-based complementary field-effect-transistors and integrated circuits with yttrium oxide Appl. Phys. Lett. 105, 063101 (2014); 10.1063/1.4892918High performance transistors via aligned polyfluorene-sorted carbon nanotubes Appl. Phys. Lett.We report on the marked improvements in key device characteristics of single walled carbon nanotube (SWCNT) field-effect transistors (FETs) by coating the active semiconductor with a fluoropolymer layer such as poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE). The observed improvements include: (i) A reduction in off-current by about an order of magnitude, (ii) a significant reduction in the variation of threshold voltage, and (iii) a reduction in bias stress-related instability and hysteresis present in device characteristics. These favorable changes in device characteristics also enhance circuit performance and the oscillation amplitude, oscillation frequency, and increase the yield of printed complementary 5-stage ring oscillators. The origins of these improvements are explored by exposing SWCNT FETs to a number of vapor phase polar molecules which produce similar effects on the FET characteristics as the PVDF-TrFE. Coating of the active SWCNT semiconductor layer with a fluoropolymer will be advantageous for the adoption of SWCNT FETs in a variety of printed electronics applications. V C 2014 AIP Publishing LLC.

Assembly and Electronic Applications of Colloidal Nanomaterials

“…[347] The difference between the intrinsic gate capacitance and the parallel-plate capacitance is more significant with lower SWCNT density or higher dielectric capacitance. [54,364] Preventing water adsorption and reducing dielectric trap states via the use of hydrophobic dielectrics, such as self-assembled nanodielectrics, [338,365] or encapsulation layers, such as AlO x [21,354] or fluoropolymers, [55,366] have proven to be effective approaches for realizing the reliable and stable operation of SWCNT FETs. [33] The on-state conductances and mobilities of selected solutionprocessed SWCNT FETs [36,43,132,155,165,207,208,213,214,236,257,296,297,338] versus channel length are shown in Figure 6F,G.…”

The Positive Effects of Hydrophobic Fluoropolymers on the Electrical Properties of MoS2 Transistors

“…This is believed to be due to the remaining oxygen to be strongly bonded to the defects and edges of the MoS2 channel [18]. Improvement in the off-current states upon coating with Teflon-AF is possibly due to the polar molecules of the fluoropolymer which will partially neutralize charged dopants [22,29]. Figure 4(b)).…”

“…Previous reports have shown that the performance variations of graphene and carbon nanotube (CNT) FETs can be reduced by applying a monolayer self-assembled hexamethyldisilazane (HMDS) layer between the back gate dielectric and the device channel or on the top surface of the device channels [18][19][20]. Other reports showed that passivating the surface of graphene and phosphorene FETs by a thicker hydrophobic film, such as fluoropolymers, results in more lasting positive changes and improved consistency in device to device performance [21][22][23].…”

Fabrication of Fluoropolymer Microtubes via RAFT Copolymerization of N,N′‐Methylene Bisacrylamide Gel Fibers and Fluoromonomer

“…During the past two decades, many different techniques have been developed to fabricate polymer tubes, such as the template method, self‐assembling method, electrostatic spinning method and so on . The coating of a fluoropolymer layer on single‐walled carbon nanotube field‐effect transistors was found to improve drastically the key device characteristics . However, fluoropolymer nano‐ and microtubes either formed from fluoropolymers or polymerized from fluoromonomers have not been investigated yet.…”