Dynamics of hydrogen sensing with Pt/TiO2 Schottky diodes

Cerchez, M.; Langer, H.; Achhab, Mhamed El; Heinzel, T.; Ostermann, D.; Lüder, Hannes; Degenhardt, J.

doi:10.1063/1.4816265

Cited by 33 publications

(55 citation statements)

References 37 publications

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“…This was hypothesized to be due to high energy impact from the sputtering process creating interfacial states thus allowing it to act more as an Ohmic contact rather than a Schottky barrier. 150,151 This work also investigated the n + Si/Ti (or more probably n + Si/TiSi x /Ti) 152 interface and showed both theoretically and experimentally that at high Si dopants levels charge could tunnel through the barrier created by the Si -TiSi x Schottky barrier, whereas at low dopant densities charge could not tunnel through this barrier. This charge transport mechanism is well illustrated in Fig.…”

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confidence: 95%

Strategies for stable water splitting via protected photoelectrodes

et al. 2017

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Photoelectrochemical (PEC) solar-fuel conversion is a promising approach to provide clean and storable fuel (e.g., hydrogen and methanol) directly from sunlight, water and CO. However, major challenges still have to be overcome before commercialization can be achieved. One of the largest barriers to overcome is to achieve a stable PEC reaction in either strongly basic or acidic electrolytes without degradation of the semiconductor photoelectrodes. In this work, we discuss fundamental aspects of protection strategies for achieving stable solid/liquid interfaces. We then analyse the charge transfer mechanism through the protection layers for both photoanodes and photocathodes. In addition, we review protection layer approaches and their stabilities for a wide variety of experimental photoelectrodes for water reduction. Finally, we discuss key aspects which should be addressed in continued work on realizing stable and practical PEC solar water splitting systems.

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confidence: 95%

Strategies for stable water splitting via protected photoelectrodes

et al. 2017

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“…In Ref. [5], it has been shown that n d saturates after 20 min of hydrogen exposure at room temperature, but this evolution has not been measured at low temperatures where this DLTS trace was started. However, after this sweep has been recorded, the sample has been sufficiently long around room temperature to ensure saturation of n d .…”

Section: Experimental Results and Interpretationmentioning

confidence: 99%

“…Also, even small concentrations of hydrogen are known to embrittle highly relevant metals like steels (). Mesoporous or nanotubular titanium dioxide‐based devices have been shown to be extremely sensitive hydrogen sensors . Typically, a catalytic electrode like Pt or Pd covers a

{TiO}_{2}

film and a Schottky barrier is formed at the interface ().…”

Section: Introductionmentioning

confidence: 99%

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Deep-level transient spectroscopy at platinum/titanium-dioxide hydrogen sensors

Schnorr

Cerchez

Ostermann³

et al. 2015

Phys. Status Solidi B

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Abstractauthoren Deep traps in platinum/mesoporous‐titanium‐dioxide hydrogen sensors are studied by deep‐level transient spectroscopy (DLTS) before, during, and after the gas detection. This is possible for atmospheric hydrogen volume fractions in the low ppm regime where the Schottky barrier at the normalPt/TiO2 interface is retained. In the absence of hydrogen, two deep levels with binding energies of 470 and 720 meV are found. Their occurrence increases as hydrogen is offered, but to a smaller extent than the hydrogen‐induced doping density. An additional level develops during hydrogen exposure at a binding energy of ≈870thinmathspacenormalmeV. After the sensing sequence, the sample recovers only partially, but the deep trap densities can be reset by annealing in dry air. The data suggest that besides donor formation, exposure of mesoporous TiO2 to hydrogen also generates deep traps. The results furthermore show that despite the large interfacial disorder, which in the present case is essential for the functionality, DLTS can be used to obtain information about deep traps generated during utilization of the device as gas sensor.

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“…Also a concept based on percolation transport through Pd cluster arrays with a resolution of 100 µm has been demonstrated [12,13]. Here, we present a hydrogen detector that combines submicrometer spatial resolution with the high sensitivity of the Pt/TiO 2 -system [14][15][16], and with the possibility of on-chip implementation by established lithographic techniques.…”

Section: Introductionmentioning

confidence: 99%