A Semiconductor‐Nanowire Assembly of Ultrahigh Junction Density by the Langmuir–Blodgett Technique

Acharya, Somobrata; Panda, Asit Baran; Belman, Nataly; Efrima, Shlomo; Golan, Yuval

doi:10.1002/adma.200501234

Cited by 111 publications

(95 citation statements)

References 29 publications

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“…Therefore, the technology to achieve network films of organic MWs deposited from a dispersion with controlled alignment and density is acutely desired. The integration of inorganic and metallic wires into functional network films has been extensively explored by using a number of methods such as the flow cell method (26), electric field (27,28), magnetic field (29), electrospinning (30), chemical and biological surface-directed patterning (31,32), Langmuir-Blodgett technique (33,34), transfer-printing (35,36,37), and the blownbubble method (38). Compared with their inorganic counterparts, however, organic wires are typically mechanically less robust, electromagnetically less active, and broader in size distribution; hence, the aforementioned alignment techniques cannot easily be applied to them.…”

mentioning

confidence: 99%

Solution-processed, high-performance n-channel organic microwire transistors

Oh¹,

Lee²,

Mannsfeld³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

222

197

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The development of solution-processable, high-performance nchannel organic semiconductors is crucial to realizing low-cost, all-organic complementary circuits. Single-crystalline organic semiconductor nano/microwires (NWs/MWs) have great potential as active materials in solution-formed high-performance transistors. However, the technology to integrate these elements into functional networks with controlled alignment and density lags far behind their inorganic counterparts. Here, we report a solutionprocessing approach to achieve high-performance air-stable nchannel organic transistors (the field-effect mobility ( ) up to 0.24 cm 2 /Vs for MW networks) comprising high mobility, solutionsynthesized single-crystalline organic semiconducting MWs ( as high as 1.4 cm 2 /Vs for individual MWs) and a filtration-and-transfer (FAT) alignment method. The FAT method enables facile control over both alignment and density of MWs. Our approach presents a route toward solution-processed, high-performance organic transistors and could be used for directed assembly of various functional organic and inorganic NWs/MWs. organic semiconductors ͉ single crystals ͉ solution processing ͉ alignment S olution-processable, high-performance n-channel (electrontransporting) organic semiconductors are indispensable for cost-effective production of all-organic, flexible complementary logic elements (1-3). To date, however, very few solutionprocessable, air-stable organic n-channel semiconductors matching the performance of amorphous silicon (a-Si) ( Ն 0.1 cm 2 /Vs) have been reported (4-8). Organic semiconductor nano/microwires (NWs/MWs) have recently emerged as promising building blocks for various electronic and optical applications such as light-emitting diodes (LEDs) (9), field-effect transistors (FETs) (10), photoswitches (11), vapor sensors (12), solar cells (13), nanoscale lasers (14), optical waveguides (15), and memory devices (16). These unique materials combine the high-performance of singlecrystalline structures with solution-processability by dispersion (17,18). Several p-channel (hole-transporting) organic wires prepared by solution-processing have exhibited Ͼ 0.1 cm 2 /Vs for singlewire transistors (19)(20)(21)(22), whereas only a few solution-synthesized n-channel organic wires have been reported, typically with low performance ( Ϸ10 Ϫ3 Ϫ 10 Ϫ2 cm 2 /Vs) (23,24).Despite the intrinsic high mobility of single-crystalline wires, precise wire placement and wire-to-wire performance variation, due to the difference in the contact quality at the wire/insulator and wire/electrode interfaces, substantially hinder successful device integration (10, 25). Therefore, the technology to achieve network films of organic MWs deposited from a dispersion with controlled alignment and density is acutely desired. The integration of inorganic and metallic wires into functional network films has been extensively explored by using a number of methods such as the flow cell method (26), electric field (27, 28), magnetic field (29), electrospinning (30),...

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mentioning

confidence: 99%

Solution-processed, high-performance n-channel organic microwire transistors

Oh¹,

Lee²,

Mannsfeld³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

222

197

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“…6610 4 lm 2 . [5,6] In this Communication, we relate the crystallographic phase and shape to the optical polarization properties upon application of an electric field to a large-scale nanorod assembly (microstrings). We demonstrate that changes in the crystallographic phase, from WZ to ZB, are accompanied by a sharp transition in the polarization-dependent optical properties of the nanorods.…”

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confidence: 99%

Polarization Properties and Switchable Assembly of Ultranarrow ZnSe Nanorods

et al. 2007

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Size-and shape-dependent optical properties of 1D semiconductor nanoparticles and their 2D or 3D assembly holds great promise in nanoscale optoelectronics. [1,2] The 1D nanoparticles are intrinsically asymmetric, suggesting unique structures, assembly, and properties. Assembly into collective structures with well-defined orientation of the particles could display a variety of interesting properties, whereas in a large assembly of asymmetric nanoparticles, random orientations of individual nanoparticles may inhibit the inherent properties of the collective behavior. An external field can be used to overcome energy barriers underpinning the random orientation in order to achieve a system revealing the inherent properties of the individual nanoparticles. The crystallographic phase of 1D nanoparticles has considerable importance in determining the inherent polarization properties that underlie their assembly. Zinc selenide, an important wide-bandgap (2.7 eV) material with a broad range of potential applications, [3,4] can exist in the hexagonal (wurtzite, WZ) or the cubic (sphalerite, zinc blende, ZB) phase (crystal structure). Recently, we reported uniform ZnSe nanorods and nanowires of ultranarrow width (1.3 nm), and their assembly into highly ordered 2D arrays with ultrahigh junction densities of ca. 6610 4 lm 2 . [5,6] In this Communication, we relate the crystallographic phase and shape to the optical polarization properties upon application of an electric field to a large-scale nanorod assembly (microstrings). We demonstrate that changes in the crystallographic phase, from WZ to ZB, are accompanied by a sharp transition in the polarization-dependent optical properties of the nanorods. Interestingly, while all previously reported works suggested optically active 1D semiconductors to be polarized along their long (c-)axis, [1,7,8] we notably show perpendicular polarization behavior in fluorescence emission when 1.3 nm wide WZ nanorods are aligned by an electric field into centimeter-long microstrings. Synthesis of shape-and phase-controlled nanorods was carried out by addition of relatively innocuous zinc acetate and selenourea precursors to controlled ratios of liganding solvents of octadecylamine (ODA) and trioctylphosphine oxide (TOPO) in the temperature range 140-220°C.[5,9] Nanoparticle shape (aspect ratio) and size could be changed from spherical to elongated particles by increasing the molar ratio of ODA in the mixed solvent.[9]Transmission electron microscopy (TEM) images of highly ordered rods prepared in pure ODA and random rods prepared in a 2:3 TOPO/ODA solvent are shown in Figure 1a and b, respectively. Notably, the width and length of the ordered rods are 1.3 and 4.5 nm, respectively, while the dimensions of random rods are significantly larger, ca. 4 nm wide and 15-40 nm long. Energy dispersive spectroscopy (EDS) analysis confirmed the 1:1 atomic ratio of Zn to Se, as expected for a stoichiometric ZnSe crystal (see Fig. S1 in the Supporting Information). The powder X-ray diffraction (XRD) patterns ...

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“…However, this method suffers from the drawbacks such as uncontrollable and low successful device yield, poor contact between metal electrode and inorganic NWs, etc. Other alternatives such as Langmuir-Blodgett (LB) technique [20,21], bubble-blown (BB) technique and non-uniform electric field assisted alignment method are investigated by researchers to overcome these drawbacks [22]. The electric field assisted alignment, which is also called dielectrophoresis (DEP), is developed to accurately manipulate the position of NWs.…”

Section: Bmentioning

confidence: 99%

Nanomaterials processing for flexible electronics

Shakthivel

Liu

Núñez

et al. 2017

2017 IEEE 26th International Symposium on Industrial Electronics (ISIE)

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Abstract-Inorganic nanomaterials such as nanowires (NWs) and nanotubes (NTs) are explored for future flexible electronics applications due to their attributes such as high aspect ratio, enhanced surface-to-volume ratio, prominent mobility and ability to integrate on non-conventional substrates. Device performance of semiconducting NWs are demonstrated to be superior compared to the organic counterparts. Among the synthesis methods, bottom-up vapour-liquid-solid (VLS) growth mechanism playing central role for preparing wide variety of high crystal quality semiconducting NWs. However, the high temperature synthesis process prevents fabrication of NW devices directly over flexible substrates which imply the investigation of efficient transfer techniques such as dry contact printing and electric field assisted assembly. Currently, many efforts are directed to study the integration techniques of NWs from growth substrates to non-conventional receiver substrates and parameters such as transfer-yield, alignment and density. These efforts will help to utlilize NWs as building blocks in future flexible electronic devices and circuits. This work focuses on VLS growth of semiconducting NWs and their transfer-printing over large area substrate to fabricate flexible electronics.

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A Semiconductor‐Nanowire Assembly of Ultrahigh Junction Density by the Langmuir–Blodgett Technique

Cited by 111 publications

References 29 publications

Solution-processed, high-performance n-channel organic microwire transistors

Solution-processed, high-performance n-channel organic microwire transistors

Polarization Properties and Switchable Assembly of Ultranarrow ZnSe Nanorods

Nanomaterials processing for flexible electronics

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