Vertical devices of self-assembled hybrid organic/inorganic monolayers based on tungsten polyoxometalates

Makarona, Eleni; Kapetanakis, E.; Velessiotis, D.; Douvas, Antonios M.; Argitis, Panagiotis; Normand, P.; Gotszalk, Teodor; Woszczyna, M.; Γλέζος, Ν.

doi:10.1016/j.mee.2008.01.020

Cited by 57 publications

(24 citation statements)

References 11 publications

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“…and a shift in the flatband voltage. Mokarana et al 33 studied the effect of APTES modification in vertical devices of self-assembled hybrid organic/inorganic monolayers on tungsten polyoxometalates (POMs) and observed decrease in the capacitance. Further, addition of APTES reduces the conductance and acts as an insulator.…”

Section: Surface Modification Aspects-uv-vis Absorption Spectroscopy-mentioning

confidence: 99%

Sensitivity Enhancement Mechanisms in Textured Dielectric based Electrolyte-Insulator-Semiconductor (EIS) Sensors

Kumar

Panda

2015

ECS J. Solid State Sci. Technol.

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The possible mechanisms governing the enhancement of sensitivities of Electrolyte-insulator-semiconductor (EIS) devices upon surface modification (texturing) realized by electrostatic attachment of silica particles using 3-aminopropyl triethoxysilane (APTES) as a linker are presented. EIS devices were fabricated with a textured dielectric surface using SiO 2 particles (of diameters 475, 135, and 70 nm) and screen printed Ag/AgCl electrodes. A maximum pH sensitivity of 52.4 mV/pH was achieved for the EIS device textured with 70 nm particle size while the sensitivity with the planar dielectric was 37.1 mV/pH. The APTES modification enhanced the adsorption of H + ions by protonation of the -NH 2 to -NH 3 + sites as seen from the capacitance versus voltage (C-V) hysteresis voltages. UV-Vis absorption and photoluminescence (PL) spectra indicated that the surface defects on the textured surface increased with decreasing particle size. Zeta potential measurements suggested a combined acid-base behavior of textured surface with the formation of -NH Electrolyte-insulator-semiconductor (EIS) based sensors are advantageous because of their small size, potential for mass production at low cost and easy integration with other silicon devices. The working principle is based on the MOS device with the electrolyte replacing the metal. Chemical sensitivity is an important performance parameter and is defined as the change in potential at the insulatorelectrolyte interface occurring with the change in the pH of the electrolyte. To improve the sensitivity, various high-K dielectric materials (such as Si 3 N 4 , Al 2 O 3 , Ta 2 O 5 , Gd 2 O 3 , Pr 2 O 3 , TiO 2 , Er 2 O 3 , Sm 2 O 3 and HoTiO 3 ) have been used to enhance the field effect interaction and the buffer capacity of the insulator. Also, their stack reduces the interface defects between the semiconductor and the insulator. 1-8The surface modification is another way by which the sensitivity can be improved. For example, Cheng et al. 9 used hydroxylated surface modified with 3-aminopropyl triethoxysilane (APTES) to show slight enhancement in the pH sensitivity and attributed the changes to the added contribution of the -NH 2 groups having higher proton affinity with improved signal-to-noise ratio. He et al.10 observed a linear pH response with the combined acidic and basic characteristics of -NH 2 and -SiOH groups on the APTES modified ZnS/silica nanocable field effect transistor. Hsu et al.11 designed a glucose sensor based on a poly-silicon wire coated with a mixture of γ-APTES and silica nanoparticles (NPs). The improved detection limit was attributed to the large specific surface area of the silica NPs cluster and the increased amount of OH-bonds. Wu et al.12 fabricated a label free DNA detection device with sensitivity in the range 1 fM-10 μM by utilizing a mixture of UV illuminated γ-APTES and silica NPs. Further, Oh et al. 13 used silicon nanowires and improved the pH sensitivity from 54.9 mV/pH to 60.2 mV/pH. Xue et al.14 fabricated a Si/SiO 2 thin-film based ion-se...

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Section: Surface Modification Aspects-uv-vis Absorption Spectroscopy-mentioning

confidence: 99%

Sensitivity Enhancement Mechanisms in Textured Dielectric based Electrolyte-Insulator-Semiconductor (EIS) Sensors

Kumar

Panda

2015

ECS J. Solid State Sci. Technol.

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“…4,5 In addition, they can be directly exploited for fast switching, diode, and memory applications as well as for chemical sensors or biosensors. Our group has already demonstrated, using planar junctions 6,7 as well as vertical junctions and STM measurements, 8 that the redox properties of the inorganic 12tungstophosphoric acid (H 3 PW 12 O 40 ), a member of the polyoxometalate (POM) class can be, in principle, exploited in novel memory structures. In the current work we extensively investigate the transport mechanisms and the charging states of hybrid organic-inorganic capacitor structures which contain POMs as the charge trapping medium.…”

mentioning

confidence: 99%

Tungsten polyoxometalate molecules as active nodes for dynamic carrier exchange in hybrid molecular/semiconductor capacitors

Balliou

Douvas

Normand

et al. 2014

Journal of Applied Physics

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Superhydrophobicity on transparent fluorinated ethylene propylene films with nano-protrusion morphology by Ar+ O2 plasma etching: Study of the degradation in hydrophobicity after exposure to the environment Photoresist modifications by plasma vacuum ultraviolet radiation: The role of polymer structure and plasma chemistry J. Vac. Sci. Technol. B 28, 993 (2010); 10.1116/1.3484249Ion beam deposition of tantalum pentoxide thin film at room temperature In this work we study the utilization of molecular transition metal oxides known as polyoxometalates (POMs), in particular the Keggin structure anions of the formula PW 12 O 40 3À , as active nodes for potential switching and/or fast writing memory applications. The active molecules are being integrated in hybrid Metal-Insulator/POM molecules-Semiconductor capacitors, which serve as prototypes allowing investigation of critical performance characteristics towards the design of more sophisticated devices. The charging ability as well as the electronic structure of the molecular layer is probed by means of electrical characterization, namely, capacitance-voltage and current-voltage measurements, as well as transient capacitance measurements, C (t), under step voltage polarization. It is argued that the transient current peaks observed are manifestations of dynamic carrier exchange between the gate electrode and specific molecular levels, while the transient C (t) curves under conditions of molecular charging can supply information for the rate of change of the charge that is being trapped and de-trapped within the molecular layer. Structural characterization via surface and cross sectional scanning electron microscopy as well as atomic force microscopy, spectroscopic ellipsometry, UV and Fourier-transform IR spectroscopies, UPS, and XPS contribute to the extraction of accurate electronic structure characteristics and open the path for the design of new devices with on-demand tuning of their interfacial properties via the controlled preparation of the POM layer. V C 2014 AIP Publishing LLC.

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“…The presence of the neutral biomolecules in the nanogap cavity is simulated by introducing material having dielectric constant (K > 1) corresponding to biomolecules (for e.g. streptavidin = 2.1 [33], protein = 2.50, biotin = 2.63 [34], and APTES = 3.57 [35]) [36] in the nanogap cavities (assuming that the cavities are completely filled with biomolecules). In order to simulate the effect of charged biomolecules, negative or positive interface fixed charge (N f = ±4 Â 10 16 m À2 ) (for e.g.…”

Section: Device Architecture and Simulationmentioning

confidence: 99%

“…To simulate the presence of biomolecules in the nanogap cavity region, an oxide layer with height of t bio = 9 nm is defined and its dielectric constant is varied as K = 2, 3, 4, 5, 7, 10. The height/thickness of the layer is so chosen such that the varying height of the biomolecules [33,35].…”

Section: Device Architecture and Simulationmentioning

confidence: 99%

Investigation of dielectric modulated (DM) double gate (DG) junctionless MOSFETs for application as a biosensors

Ajay

Narang

Saxena

et al. 2015

Superlattices and Microstructures

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Vertical devices of self-assembled hybrid organic/inorganic monolayers based on tungsten polyoxometalates

Cited by 57 publications

References 11 publications

Sensitivity Enhancement Mechanisms in Textured Dielectric based Electrolyte-Insulator-Semiconductor (EIS) Sensors

Sensitivity Enhancement Mechanisms in Textured Dielectric based Electrolyte-Insulator-Semiconductor (EIS) Sensors

Tungsten polyoxometalate molecules as active nodes for dynamic carrier exchange in hybrid molecular/semiconductor capacitors

Investigation of dielectric modulated (DM) double gate (DG) junctionless MOSFETs for application as a biosensors

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