Photodetachment of WO−3: The electron affinity of WO3

Walter, C. W.; Hertzler, Ch.; Devynck, P.; Smith, Gregory P.; Peterson, J. R.

doi:10.1063/1.461089

Cited by 47 publications

(25 citation statements)

References 10 publications

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“…4b As discussed so far, oxygen adsorption/desorption on and from material surfaces are general occurrences and can dominate the conduction of nanowires with the thickness of the depletion layer. 29 This phenomenon produced conduction and valence band offsets of 1.47 and 0.87 eV, respectively. 1.…”

Section: Resultsmentioning

confidence: 99%

An edge-contacted pn-heterojunction of a p-SWCNT/n-WO3 thin film

2013

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We report a heterojunction formed between single-wall carbon nanotubes (SWCNTs) and a WO 3 thin film. WO 3 thin films were fabricated by sputter deposition of W followed by oxidation and SWCNTs were fabricated by the arc-discharge method. The morphology of the structures was examined by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The current-voltage characteristics of WO 3 thin films, SWCNTs films, and SWCNT/WO 3 heterojunctions were measured in darkness and under ultraviolet light. A rectifying heterojunction formation of p-SWCNT/n-WO 3 was confirmed. The observed unconventional optoelectronic properties were analyzed, and the results were used to explain the photoconduction phenomena occurring at the heterojunction. The heterojunctions and resistors were also examined for their photodetection performance. Experimentalp-SWCNT/n-WO 3 heterojunction preparation: SiO 2 (300 nm)/Si substrates were sequentially ultrasonicated in acetone, methanol, and deionized water for 15 min each and then blow dried

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Section: Resultsmentioning

confidence: 99%

An edge-contacted pn-heterojunction of a p-SWCNT/n-WO3 thin film

2013

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“…The average leakage current under negative formation (NF) is 229.7 pA at a read voltage (V read ) of -2.0 V, while it is 673.3 pA under PF at a V read of +2.0 V. Asymmetry values of the leakage currents under NF and PF polarities are quite reasonable due to the different work function (Φ m ) values of IrO x [(Φ m ) IrOx ≈ 5.2 eV [14], and of W [(Φ m ) W ≈ 4.3-4.91 eV [29]] electrodes. Considering the electron affinities ( χ ) of 3.33 eV [30] for WO 3 and 1.25 eV for Al 2 O 3 layers, the values of the effective barrier heights (Φ b ) are found to be [Φ b = (Φ m ) W -( χ ) WO3 ] 1.3 eV and [(Φ b ) = (Φ m ) IrOx -( χ ) Al2O3 ] 3.95 eV, respectively. So the electron injection at the IrO x /Al 2 O 3 interface will be lower than that of the W/WO x interface.…”

Section: Resultsmentioning

confidence: 99%

Formation polarity dependent improved resistive switching memory characteristics using nanoscale (1.3 nm) core-shell IrOx nano-dots

et al. 2012

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Improved resistive switching memory characteristics by controlling the formation polarity in an IrOx/Al2O3/IrOx-ND/Al2O3/WOx/W structure have been investigated. High density of 1 × 1013/cm2 and small size of 1.3 nm in diameter of the IrOx nano-dots (NDs) have been observed by high-resolution transmission electron microscopy. The IrOx-NDs, Al2O3, and WOx layers are confirmed by X-ray photo-electron spectroscopy. Capacitance-voltage hysteresis characteristics show higher charge-trapping density in the IrOx-ND memory as compared to the pure Al2O3 devices. This suggests that the IrOx-ND device has more defect sites than that of the pure Al2O3 devices. Stable resistive switching characteristics under positive formation polarity on the IrOx electrode are observed, and the conducting filament is controlled by oxygen ion migration toward the Al2O3/IrOx top electrode interface. The switching mechanism is explained schematically based on our resistive switching parameters. The resistive switching random access memory (ReRAM) devices under positive formation polarity have an applicable resistance ratio of > 10 after extrapolation of 10 years data retention at 85°C and a long read endurance of 105 cycles. A large memory size of > 60 Tbit/sq in. can be realized in future for ReRAM device application. This study is not only important for improving the resistive switching memory performance but also help design other nanoscale high-density nonvolatile memory in future.

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“…Ultrafast response of the tungstite and tungsten oxide decorated MWCNT UV photo detectors are explained in Fig. 9b, c. The electron affinity (EA) of the molecule, as determined by several process, such as, photodetachment threshold, charge transfer threshold, flame equilibrium etc., lies in the range 3.2-4.0 eV [8,34]. Work function of MWCNT is reported to be ~ 4.53 eV [35].…”

Section: Uv Detection Mechanismmentioning

confidence: 98%

Expeditious UV detection of tungstite (WO3·H2O) and tungsten oxide (WO3) decorated multiwall carbon nanotubes (MWCNT) based photodetector: ultrafast response and recovery time

et al. 2019

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Tungstite (WO 3 ·H 2 O) and tungsten oxide (WO 3 ) decorated multi-walled carbon nanotube (MWCNT) based ultra-fast UV photodetectors were fabricated and characterized in this work. Tungstite was synthesized by wet chemical route and tungsten oxide was derived by calcinating tungstite at elevated temperatures (723 K and 1023 K). The crystal structures of tungstite and tungsten oxide were confirmed from X-ray diffraction analysis. The UV photo responsive behavior of the tungstite and tungsten oxide decorated MWCNT UV photodetectors were studied using 365 nm UV LED array in the intensity range 15-83 μW cm −2 . The device showed good UV photoresponsivity with high external quantum efficiency (EQE). Tungstite decorated MWCNT UV photodetector exhibited maximum responsivity of 7.4 AW −1 along with EQE of 2550% under the incident UV intensity of 15 μW cm −2 . Up to 500 Hz optical chopping frequency, the devices showed remarkable stability along with good repeatability of UV detection. Response and recovery time is recorded as low as 400 μs and 500 μs respectively for tungstite decorated UV photodetectors.

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Photodetachment of WO−3: The electron affinity of WO3

Cited by 47 publications

References 10 publications

An edge-contacted pn-heterojunction of a p-SWCNT/n-WO3 thin film

An edge-contacted pn-heterojunction of a p-SWCNT/n-WO3 thin film

Formation polarity dependent improved resistive switching memory characteristics using nanoscale (1.3 nm) core-shell IrOx nano-dots

Expeditious UV detection of tungstite (WO3·H2O) and tungsten oxide (WO3) decorated multiwall carbon nanotubes (MWCNT) based photodetector: ultrafast response and recovery time

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