Optical and electrical characterization of CuO/ZnO heterojunctions

Yatskiv, Roman; Tiagulskyi, Stanislav; Grym, Jan; Vaniš, J.; Bašinová, Nikola; Horák, P.; Torrisi, A.; Ceccio, G.; Vacı́k, J.; Vrňata, Martin

doi:10.1016/j.tsf.2019.137656

Cited by 31 publications

(13 citation statements)

References 37 publications

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“…The ZnO NRs were grown on seeding layers by chemical bath deposition (CBD) from equimolar aqueous solutions consisting of 50 mM zinc nitrate hexahydrate and hexamethylentetramine at 95 °C for 2 h [ 35 ]. The NRs were prepared on a silicon substrate for the NAP-XPS measurements, while for the investigation of the sensing properties, alumina substrates with Pt electrodes were used ( Figure 1 ).…”

Section: Methodsmentioning

confidence: 99%

New Insights towards High-Temperature Ethanol-Sensing Mechanism of ZnO-Based Chemiresistors

Piliai

Tomeček

Hruška

et al. 2020

Sensors

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In this work, we investigate ethanol (EtOH)-sensing mechanisms of a ZnO nanorod (NRs)-based chemiresistor using a near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS). First, the ZnO NRs-based sensor was constructed, showing good performance on interaction with 100 ppm of EtOH in the ambient air at 327 °C. Then, the same ZnO NRs film was investigated by NAP-XPS in the presence of 1 mbar oxygen, simulating the ambient air atmosphere and O2/EtOH mixture at the same temperature. The partial pressure of EtOH was 0.1 mbar, which corresponded to the partial pressure of 100 ppm of analytes in the ambient air. To better understand the EtOH-sensing mechanism, the NAP-XPS spectra were also studied on exposure to O2/EtOH/H2O and O2/MeCHO (MeCHO = acetaldehyde) mixtures. Our results revealed that the reaction of EtOH with chemisorbed oxygen on the surface of ZnO NRs follows the acetaldehyde pathway. It was also demonstrated that, during the sensing process, the surface becomes contaminated by different products of MeCHO decomposition, which decreases dc-sensor performance. However, the ac performance does not seem to be affected by this phenomenon.

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Section: Methodsmentioning

confidence: 99%

New Insights towards High-Temperature Ethanol-Sensing Mechanism of ZnO-Based Chemiresistors

Piliai

Tomeček

Hruška

et al. 2020

Sensors

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“…It is well known that when the MicroCuZn alloy is used in a catalytic process, oxidation of Cu and Zn takes place, which leads to formation of CuO, Cu 2 O, ZnO. 23,79 Furthermore, when ZnO and Cu x O combine, a (p-n) heterojunction is formed, 80,81 which is effective in enhanced utilization of photoenergy and modulation of e À /h + recombination. Though it is challenging to pin point electron excitation and transfer within a complex alloy (and subsequent oxidized form of the alloy) through measurements, reasonable analysis can be made and conclusions can be drawn from the energetic band positioning of the oxidized forms of Cu and Zn.…”

Section: Hydroxyl Radical Productionmentioning

confidence: 99%

Photocatalytic activity of micron-scale brass on emerging pollutant degradation in water: mechanism elucidation and removal efficacy assessment

2020

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“…Hetero-junction devices always remain the center of attention for their eclectic range of applicability in rectifying diodes, lasing devices, photodetectors, light emitting diodes and transistors, etc [1][2][3][4][5]. However, for a longer time, these optoelectronic devices remained dependent on a costly and sophisticated silicon based technology.…”

Section: Introductionmentioning

confidence: 99%

“…However, for a longer time, these optoelectronic devices remained dependent on a costly and sophisticated silicon based technology. In contrast to this, in recent years, metal oxide based hetero-junction devices received significant attention because of their low cost, easy and eco-friendly fabrication technologies [3][4][5][6][7]. Apart from the optoelectronic applications of the metal oxide based hetero-junctions, the gas sensing devices have shown augmented device performances towards many hazardous gases [6,7].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of n-ZnO/p-Si++ Hetero-junction Devices for Hydrogen Detection: Effect of Annealing Temperature

Kumar

Rawal

Kumar

2021

Preprint

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In the present study, we reports the fabrication of n-ZnO/p-Si++ hetero-junction devices for the detection of hydrogen leakage in ambient air environment. For the fabrication of n-ZnO/p-Si++ hetero-junction devices, high quality ZnO thin films are grown by controlled thermal evaporation technique on the highly doped p-type silicon substrates at 400 oC. The two sets of films deposited at 400 o C are further annealed at 500 and 600 oC to examine the effect of annealing temperature on the structural, morphology, electrical and gas sensing properties of the deposited films. It is revealed from the x-ray diffraction studies that the crystallite size, and the density of the films increase from 22.55 to 24.95 nm, from 5.65 to 5.68 g/cm3, respectively, on increasing the fabrication temperature from 400 to 600 oC. In contrast to it, the grain boundary specific surface area decrease from 8.79 x107 to 7.88 x107 m-1 on changing the fabrication temperature from 400 to 600 oC. The hydrogen gas sensing response of the fabricated devices has also been recorded at different operating temperatures and different hydrogen concentrations (200 to 1000ppm) in air ambient. It is found that the gas sensing response of the fabricated devices increase with increase in operating temperature (up to 100 oC) and decease beyond this temperature. The gas sensing responses of the devices fabricated at 400, 500 and 600 oC are found to be 97.22, 64.23 and 40.77 % at 1000 ppm of hydrogen. A decrease in gas sensing response with fabrication temperature is attributed to the increase in crystallite size (quantum size effect), density of films (i.e. lower penetration) and decrease in grain boundary specific surface area (i.e. active sites) with annealing temperature. The mechanism of the gas sensing in these devices has also been systematically analyzed under different models.

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Optical and electrical characterization of CuO/ZnO heterojunctions

Cited by 31 publications

References 37 publications

New Insights towards High-Temperature Ethanol-Sensing Mechanism of ZnO-Based Chemiresistors

New Insights towards High-Temperature Ethanol-Sensing Mechanism of ZnO-Based Chemiresistors

Photocatalytic activity of micron-scale brass on emerging pollutant degradation in water: mechanism elucidation and removal efficacy assessment

Fabrication of n-ZnO/p-Si++ Hetero-junction Devices for Hydrogen Detection: Effect of Annealing Temperature

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