Electrical transport in passivated Pt∕TiO2∕Ti Schottky diodes

Dittrich, Th.; Zinchuk, V. M.; Skryshevsky, V. A.; Urban, I.; Hilt, Oliver

doi:10.1063/1.2135890

Cited by 34 publications

(22 citation statements)

References 17 publications

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“…Figure 6 shows the I-V behavior of TiO 2 nanotubes. The nature of the I-V curves are similar to those in [7], where at lower potentials the currents depend exponentially on the potential, which is typical for diodes. At potentials higher than a certain value, the I-V curves follow a power law (characteristic of space-charge limitation).…”

Section: Resultsmentioning

confidence: 72%

“…These Schottky barriers can limit transistor conductance in the "ON" state, and reduce the current delivery capability-a key determinant of device performance [6]. Pt/TiO 2 /Ti Schottky diodes were previously investigated by current-voltage analysis, photoresponse [7]. The Schottky barrier height (1.2-1.3 eV) between Pt and TiO 2 was determined to be based on work functions of Pt and Ti.…”

Section: Introductionmentioning

confidence: 99%

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Current voltage analysis and band diagram of Ti/TiO2 nanotubes Schottky junction

et al. 2012

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Here, we report on how the energy band diagram of a nanostructured semiconductor-metal interface aligns in accordance with semiconductor morphology. Electrochemically, titanium metal is anodized to form titanium dioxide nanotubes, which forms a junction with the free Ti substrate and this junction forms a natural Schottky barrier. With reduced dimensionality of the nanotube structures (lower wall thickness), we have observed band edge movements and band gap quantum confinement effects and lowering of the Schottky barrier. These results were corroborated with the help of cyclic voltammetry, ultraviolet-visible spectrometry, and impedance analysis. Current voltage analysis of the Schottky barrier showed a lowering of the barrier (by 25 %) with reducing dimensionality of the nanotube structures. At externally applied voltages higher than the Schottky barrier, charges can travel along the nanotubes and reside at an interface between the nanotubes and a high-κ dielectric. This property was utilized to develop high surface area solid-state capacitors.

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Section: Resultsmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Current voltage analysis and band diagram of Ti/TiO2 nanotubes Schottky junction

et al. 2012

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“…Fig. 8 Time evolution of the jump diffusion coefficient as extracted from RWNS calculations (solid line) and prediction of the multipletrapping theoretical formula of eqn (29).…”

Section: Discussionmentioning

confidence: 99%

“…First, eqn (25) contains no approximations, therefore numerical integration of eqn (25) should give very accurate results compared to the RWNS, provided that the statistics is sufficiently large. On another hand, eqn (29) gives a closed analytical formula though by using some approximations, therefore some deviations from RWNS calculations may be expected. These results are analyzed below.…”

Section: Calculation Of the Jump Diffusion Coefficient In Rwnsmentioning

confidence: 99%

Interpretation of diffusion coefficients in nanostructured materials from random walk numerical simulation

Anta

Mora‐Seró

Dittrich

et al. 2008

Phys. Chem. Chem. Phys.

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We make use of the numerical simulation random walk (RWNS) method to compute the ''jump'' diffusion coefficient of electrons in nanostructured materials via mean-square displacement. First, a summary of analytical results is given that relates the diffusion coefficient obtained from RWNS to those in the multiple-trapping (MT) and hopping models. Simulations are performed in a three-dimensional lattice of trap sites with energies distributed according to an exponential distribution and with a step-function distribution centered at the Fermi level. It is observed that once the stationary state is reached, the ensemble of particles follow Fermi-Dirac statistics with a well-defined Fermi level. In this stationary situation the diffusion coefficient obeys the theoretical predictions so that RWNS effectively reproduces the MT model. Mobilities can be also computed when an electrical bias is applied and they are observed to comply with the Einstein relation when compared with steady-state diffusion coefficients. The evolution of the system towards the stationary situation is also studied. When the diffusion coefficients are monitored along simulation time a transition from anomalous to trap-limited transport is observed. The nature of this transition is discussed in terms of the evolution of electron distribution and the Fermi level. All these results will facilitate the use of RW simulation and related methods to interpret steady-state as well as transient experimental techniques.

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“…The electron affinity of PdO (ca. 5.5 eV) is larger than the work function of Pd [26], and various defect and impurity levels are easily produced at the M/TiO2 interface [27,28]. On the other hand, Pd and Pt in the bulk of the Pd-64Pt electrode was alloyed and the alloy Pd-Pt phase in the bulk is likely to be chemically and thermally stable as a metal at elevated temperatures, even in air [19,21].…”

Section: Basic Diode Characteristics and H2-sensing Properties In Drymentioning

confidence: 99%

CO-Sensing Properties of Diode-Type Gas Sensors Employing Anodized Titania and Noble-Metal Electrodes under Hydrogen Atmosphere

2018

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CO-sensing properties of diode-type sensors employing an anodized TiO 2 film and noble-metal (M) electrodes (M/TiO 2 sensor, M: Pd, Pt, and Pd-nPt, n: the amount of Pt (wt %) in the Pd-nPt electrode) were investigated at 50-250 • C in dry or wet H 2 . All the M/TiO 2 sensors showed nonlinear I-V characteristics as a diode device in air and N 2 , but the I-V characteristics of the sensors were actually linear in H 2 because of the negligible small height of Schottky barrier at their M/TiO 2 interface. The Pd/TiO 2 sensor showed no CO response in H 2 , but the Pt/TiO 2 and Pd-nPt/TiO 2 sensors responded to CO in H 2 . Among them, the Pd-64Pt/TiO 2 sensor showed the largest CO response at 100 • C in H 2 . The reason why the mixing of Pd with Pt was effective in improving the CO response is probably because of a decrease in the amount of dissolved hydrogen species, an increase in the amount of dissociatively adsorbed hydrogen species, and an increase in the amount of adsorbed CO species in CO balanced with H 2 by the mixing of Pt into Pd. The interference from moisture in the target gas on the CO response should be largely improved from a practical application perspective.

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Electrical transport in passivated Pt∕TiO2∕Ti Schottky diodes

Cited by 34 publications

References 17 publications

Current voltage analysis and band diagram of Ti/TiO2 nanotubes Schottky junction

Current voltage analysis and band diagram of Ti/TiO2 nanotubes Schottky junction

Interpretation of diffusion coefficients in nanostructured materials from random walk numerical simulation

CO-Sensing Properties of Diode-Type Gas Sensors Employing Anodized Titania and Noble-Metal Electrodes under Hydrogen Atmosphere

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