Recent developments in semiconducting thin-film gas sensors

Sberveglieri, G.

doi:10.1016/0925-4005(94)01278-p

Cited by 475 publications

(236 citation statements)

References 61 publications

Supporting

Mentioning

231

Contrasting

Unclassified

Order By: Relevance

“…For sensing performances, outstanding results were obtained when the sensors were transformed from thick metal oxide layer devices (first generation metal oxide based gas sensors) to one with thin metal oxide layer (second generation metal oxide based gas sensors). [1] It has also been shown that the highest sensing responses can be obtained in the films with nanodimensional grains. [2] Thus, the sensing properties of thin films based on metal oxides, as well as the benefits, obtained from the addition of catalytic metals (Au, Pt, Pd), in terms of sensor's stability and selectivity have been investigated.…”

Section: Introductionmentioning

confidence: 91%

Nanowires of metal oxides for gas sensing applications

Kačiulis

Pandolfi

Comini

et al. 2008

Surface & Interface Analysis

View full text Add to dashboard Cite

Nanowires of different metal oxides (SnO 2 , ZnO) have been grown by evaporation-condensation process. Their chemical composition has been investigated by using XPS. The standard XPS quantification through main photoelectron peaks, modified Auger parameter and valence band spectra were examined for the accurate determination of oxidation state of metals in the nanowires.Morphological investigation has been conducted by acquiring and analyzing the SEM images. For the simulation of working conditions of sensor, the samples were annealed in ultra high vacuum (UHV) up to 500 • C and XPS analysis repeated after this treatment. Finally, the nanowires of SnO 2 have were used to produce a novel gas sensor based on Pt/oxide/SiC structure and operating as Schottky diode.

show abstract

Section: Introductionmentioning

confidence: 91%

Nanowires of metal oxides for gas sensing applications

Kačiulis

Pandolfi

Comini

et al. 2008

Surface & Interface Analysis

View full text Add to dashboard Cite

show abstract

“…Sensing applications [1,2] benefit directly from this pronounced surface influence on electrical characteristics. Metal oxides in general and ZnO thin films in particular have already shown a good ultra-violet (UV) [3] and gas-sensing [4] ability due to the instability of oxygen at the surface [5][6][7]. As the surface influence is increased in nanowires, greatly enhanced sensitivity is expected from nanowire devices [1,6].…”

mentioning

confidence: 99%

Persistent ion beam induced conductivity in zinc oxide nanowires

Johannes

Niepelt

Gnauck

et al. 2011

Applied Physics Letters

View full text Add to dashboard Cite

We report persistently increased conduction in ZnO nanowires irradiated by ion beam with various ion energies and species. This effect is shown to be related to the already known persistent photo conduction in ZnO and dubbed persistent ion beam induced conduction. Both effects show similar excitation efficiency, decay rates and chemical sensitivity. Persistent ion beam induced conduction will potentially allow countable (i.e. single dopant) implantation in ZnO nanostructures and other materials showing persistent photo conduction.The one dimensional geometry of nanowires leads to an immense surface to volume ratio and the path of any current through the wire is always close to the surface. Sensing applications [1,2] benefit directly from this pronounced surface influence on electrical characteristics. Metal oxides in general and ZnO thin films in particular have already shown a good ultra-violet (UV) [3] and gas-sensing [4] ability due to the instability of oxygen at the surface [5][6][7]. As the surface influence is increased in nanowires, greatly enhanced sensitivity is expected from nanowire devices [1,6]. Although the conductivity of ZnO can easily be increased by three orders of magnitude by UV excitation, the current only returns to the relaxed value very slowly due to the known Persistant Photo Conduction (PPC) effect [6,[8][9][10].In this work, we report that an analogue Persistant Ion beam induced Conduction (PIC) arises during ion irradiation. PIC may allow single ion detection in individual ZnO nanowires, as well as countable doping with single dopants into ZnO nanowires. The strongly localized energy deposition of a single ion impact can result in a change in the properties of the entire device, providing a localized probe to understand the underlying excitation mechanisms.The typical lifetime of charge carriers in ZnO nanostructures is in the order of 100 ps [11]. To contribute to a persistent current increase, excited charge carriers have to populate distinct, stable states. According to Prades et al. [6] these are surface-oxygen bound states. Further discussion on the origin and properties of PPC can be found in literature [1, 6-10, 12, 13]. For PIC discussed in this work, ions instead of UV photons generate electron hole pairs in the semiconductor. By qualitative comparison we show that PIC and PPC rely on the same mechanism.The ZnO nanowires used for this work were grown via vapor-liquid-solid growth [14][15][16] and have a typical diameter range of 150 to 250 nm. They were imprinted onto the desired substrate by lightly pushing the substrate across the densly covered growth sample. Via photolithography and electron-beam evaporation, Ti/Au 50/50 nm contact pads were defined onto the sparsely * andreas.johannes@uni-jena.de covered substrate. Some wires span the 5 µm space between contact pads (see inset figure 1). Superfluous wires were easily cut with a focused ion beam to reliably manufacture single, contacted nanowires with this randomsuccess method. The nanowire devices were then contacted a...

show abstract

“…Till date, there are numerous reports on the undoped and doped metal oxide semiconducting sensors to sense different gases [9][10][11][12] . There are many reports on NO 2 gas sensors such as, SnO 2 13 , NiO 14 , ZnO [15][16][17] based sensors.…”

Section: Introductionmentioning

confidence: 99%

“…There are many reports on NO 2 gas sensors such as, SnO 2 13 , NiO 14 , ZnO [15][16][17] based sensors. Among all the existing metal oxide gas sensors, ZnO based sensors are attracting wide attention when it is doped with Al due to the high sensitivity towards NO 2 and selectivity among other gases 9,15,18,23 . Also there are many fabrication techniques have been introduced in literature to synthesize Al doped ZnO sensors 15,16,19,20,2123,24 .…”

Section: Introductionmentioning

confidence: 99%

Effect of RF power on the structural, optical and gas sensing properties of RF-sputtered Al doped ZnO thin films

Srinatha

Kamble³

et al. 2016

RSC Adv.

View full text Add to dashboard Cite

The effect of Radio Frequency (RF) power on the properties of magnetron sputtered Al doped ZnO thin films and the related sensor properties are investigated. A series of 2 wt% Al doped ZnO; Zn0.98Al0.02O (AZO) thin films prepared with magnetron sputtering at different RF powers, are examined. The structural results reveal a good adhesive nature of thin films with quartz substrates as well as increasing thickness of the films with raising RF power. Besides, the increasing RF power is found to improve the crystallinity and grains growth as confirmed by X-ray diffraction. On the other hand, the optical transmittance is significantly influenced by the RF power, where the transparency values achieved are higher than 82% for all the AZO thin films and the estimated optical band gap energy is found to decrease with RF power due to an increase in the crystallite size as well as the film thickness. In addition, the defect induced luminescence at low temperature (77 K) and room temperature (300 K) was studied through photoluminescence spectroscopy, it is found that the defect density of electronic states of Al 3+ ion found to increase with increase of RF power due to the increase in the thickness of the film and the crystallite size. The gas sensing behavior of AZO films was studied for NO2 at 350 °C. The AZO film shows good response towards NO2 gas and also a good relationship between the response and the NO2 concentration, which is modeled using an empirical formula. The sensing mechanism of NO2 is discussed.

show abstract

Recent developments in semiconducting thin-film gas sensors

Cited by 475 publications

References 61 publications

Nanowires of metal oxides for gas sensing applications

Nanowires of metal oxides for gas sensing applications

Persistent ion beam induced conductivity in zinc oxide nanowires

Effect of RF power on the structural, optical and gas sensing properties of RF-sputtered Al doped ZnO thin films

Contact Info

Product

Resources

About