Small π-conjugated organic molecules based transistor and inverter with Cu electrodes

Yadav, Sarita; Srivastava, Pawan Kumar; Ghosh, Subhasis

doi:10.1016/j.orgel.2013.09.008

Cited by 6 publications

(2 citation statements)

References 23 publications

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“…At optimized growth condition, the surface morphologies of CuPc films have anisotropic elongated grains which increase the effective contact area between the source-drain electrodes and the organic layer, resulting in reduction of the contact resistance. Pentacene and CuPc were grown at optimized growth conditions , of a very low evaporation rate of 0.1 Å/s and substrate temperature of 40 and 100 °C, respectively. Pentacene thin film growth is combination of diffusion limited aggregation (DLA) and vertical mound growth.…”

Section: Resultsmentioning

confidence: 99%

Amorphous Strontium Titanate Film as Gate Dielectric for Higher Performance and Low Voltage Operation of Transparent and Flexible Organic Field Effect Transistor

Yadav

Ghosh

2016

ACS Appl. Mater. Interfaces

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We report that the pervoskite material, strontium titanate (STO) can be used as a gate dielectric layer of flexible and low voltage organic field effect transistor (OFET). The crystallinity, dielectric constant, and surface morphology of STO films can be controlled by the engineering of the growth condition. Under optimized growth condition, amorphous films of STO show a much better gate dielectric compared to other gate dielectrics used to date, with very small leakage current density for flexible and low voltage (<5 V) OFETs. The amorphous STO film decreases the interface trap density at organic/dielectric interface substantially. Pentacene transistors with amorphous STO gate dielectric show high mobility of 2 cm(2)/(V s), on/off ratio of 10(6), subthreshold swing of 0.3 V/dec and low interface trap density. Similarly excellent performance has been obtained in copper phthalocyanine (CuPc) based OFETs with on/off ratio ∼10(5) and carrier mobility ∼5.9 × 10(-2) cm(2)/(V s). Moreover, the operating voltage (∼5 V) has been reduced by more than one order of magnitude. It has been demonstrated that the low processing temperature of amorphous STO makes it the most suitable gate dielectric for flexible and transparent organic devices to operate under low voltage.

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Section: Resultsmentioning

confidence: 99%

Amorphous Strontium Titanate Film as Gate Dielectric for Higher Performance and Low Voltage Operation of Transparent and Flexible Organic Field Effect Transistor

Yadav

Ghosh

2016

ACS Appl. Mater. Interfaces

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“…The main difficulty in achieving ambipolar transistor is the injection of electrons and holes from same metal electrode into single organic semiconductor. It requires that the band gap of organic materials should be low and the work function of metal electrodes is such that it can easily inject holes in the highest occupied molecular orbital (HOMO) as well as electrons in the lowest unoccupied molecular orbital (LUMO) of organic materials [7]. There are different approaches to realize ambipolar transport in OFETs using [8]; (a) single organic molecule which can transport both type of charge carriers [9][10][11][12][13][14], (b) blend of donor and acceptor organic molecules [15][16][17], and (c) heterojunction of donor and acceptor organic molecules [18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Study of accumulation channel thickness determined by heterojunction of donor and acceptor organic semiconductors with similar and dissimilar molecular structure

Yadav¹,

Ghosh²

2020

Phys. Scr.

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In organic field effect transistors (OFETs), the accumulation channel for charge transport occurs within few layers on the top of gate dielectric. However this is the most poorly known parameter in OFETs, as it is extremely difficult to determine the charge accumulation thickness experimentally in unipolar OFETs. With the main objective to determine the thickness of accumulation channel, we have fabricated heterojunction OFETs using donor and acceptor organic semiconductors with similar (CuPc & F16CuPc) and dissimilar (pentacene & F16CuPc) molecular structure. The transistor characteristics of OFETs based on the organic heterojunction of similar and dissimilar molecular structure changed from unipolar transport (normally off) to normally on or unipolar to ambipolar transport by varying the bottom layer thickness and deposition order of organic molecules in the heterojunction. In normally off transistors, no conducting channel exist at zero gate bias whereas in normally on transistors, a conducting channel exist at heterojunction interface at zero gate bias. In ambipolar OFETs, the ambipolar charge transport occurs when the bottom layer thickness is ≥3 nm and in normally on OFETs, when the bottom layer is ≥10 nm the normally on transistor becomes normally off due to the shifting of the field effect channel farther from the heterojunction channel. Therefore, from the transistor characteristics of ambipolar and normally on OFETs based on heterojunction of semiconductors with similar and dissimilar molecular structure, the charge accumulation thickness at organic/gate dielectric interface has been found to be ∼3 nm and the charge accumulation thickness at heterojunction interface is ∼10 nm.

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Novel pull–push organic switches with D–π–A structural designs: computational design of star shape organic materials

et al. 2022

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Small π-conjugated organic molecules based transistor and inverter with Cu electrodes

Cited by 6 publications

References 23 publications

Amorphous Strontium Titanate Film as Gate Dielectric for Higher Performance and Low Voltage Operation of Transparent and Flexible Organic Field Effect Transistor

Amorphous Strontium Titanate Film as Gate Dielectric for Higher Performance and Low Voltage Operation of Transparent and Flexible Organic Field Effect Transistor

Study of accumulation channel thickness determined by heterojunction of donor and acceptor organic semiconductors with similar and dissimilar molecular structure

Novel pull–push organic switches with D–π–A structural designs: computational design of star shape organic materials

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