Enhancement of the hydrogen gas sensitivity by large distribution of c -axis preferred orientation in highly Ga-doped ZnO polycrystalline thin films

Nulhakim, Lukman; Makino, Hisao; Kishimoto, S.; Nomoto, Junichi; Yamamoto, Tetsuya

doi:10.1016/j.mssp.2017.06.045

Cited by 15 publications

(11 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Instead, doping by Ga(III) and In(III), that have a ionic radii closer to that of Zn(II), is more often in use [4,5]. It was demonstrated that doping ZnO with Ga improved not only the conductivity, but also the sensitivity to various toxic or flammable gases, e.g., CO, formaldehyde, H 2 , ammonia, and methane [10,13,14,15,16,17]. The influence of doping on sensitivity is often attributed to electronic effects at the semiconductor surface [13,10], while the chemical aspect of gas molecules reception on the doped ZnO surface is overlooked.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of CO and OH adsorption on in-doped ZnO surfaces

Saniz

Sarmadian

Partoens

et al. 2019

Journal of Physics and Chemistry of Solids

View full text Add to dashboard Cite

We present a first-principles computational study of CO and OH adsorption on non-polar ZnO (1010) surfaces doped with indium. The calculations were performed using a model ZnO slab. The position of the In dopants was varied from deep bulk-like layers to the surface layers. It was established that the preferential location of the In atoms is at the surface by examining the dependence of the defect formation energy as well as the surface energy on In location. The adsorption sites on the surface of ZnO and the energy of adsorption of CO molecules and OH-species were determined in connection to In doping. It was found that OH has higher bonding energy to the surface than CO. The presence of In atoms at the surface of ZnO is favorable for CO adsorption, resulting in an elongation of the C-O bond and in charge transfer to the surface. The effect of CO and OH adsorption on the electronic and conduction properties of surfaces was assessed. We conclude that In-doped ZnO surfaces should present a higher electronic response upon adsorption of CO.

show abstract

Section: Introductionmentioning

confidence: 99%

First-principles study of CO and OH adsorption on in-doped ZnO surfaces

Saniz

Sarmadian

Partoens

et al. 2019

Journal of Physics and Chemistry of Solids

View full text Add to dashboard Cite

show abstract

“…The growth of the lower conductive space charge region upon the capriciously scattered ZnO grains results into the development of potential barriers between two grains [45,46] (i.e. at the grain boundaries) as shown in Fig.…”

Section: Grain Boundary Current Control Modelmentioning

confidence: 99%

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

Kumar

Rawal

Kumar

2021

Preprint

View full text Add to dashboard Cite

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.

show abstract

“…This study provided a method for the development of a gas-sensitive material with organic-inorganic hybrid nanocomposites. Nulhakim et al prepared highly Ga-doped ZnO polycrystalline thin films deposited by radio-frequency magnetron sputtering for hydrogen gas sensing (Nulhakim et al, 2017). The relationship between the microstructure of preferred c-axis-oriented thin films and the hydrogen gas-sensing performance was introduced.…”

Section: Research Status Of Metal Oxides For Gas Sensorsmentioning

confidence: 99%

Gas-Sensing Performances of Metal Oxide Nanostructures for Detecting Dissolved Gases: A Mini Review

Guan

Tang²,

et al. 2020

Front. Chem.

View full text Add to dashboard Cite

Gas sensors have been wildly used in various fields related to people's lives. Gas sensor materials were the core factors that affected the performances of various gas sensors, and these have attracted much attention from scientific researchers due their high sensitivity, high selectivity, adjustable reliability, low cost, and other advantages. The preparation of nanostructures with a highly specific surface area was a useful method to improve the gas-sensing performance of a metal oxide semiconductor. Meanwhile, lots of research has focused on preparing nanostructures with a highly specific surface area. This paper has explored some fabricated sensors with high sensitivity, good selectivity, and long-term stability, which has also made them promising candidates for toxic gas detection. Besides, this paper has reviewed the development status of metal oxides used as gas sensors.

show abstract

Enhancement of the hydrogen gas sensitivity by large distribution of c -axis preferred orientation in highly Ga-doped ZnO polycrystalline thin films

Cited by 15 publications

References 31 publications

First-principles study of CO and OH adsorption on in-doped ZnO surfaces

First-principles study of CO and OH adsorption on in-doped ZnO surfaces

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

Gas-Sensing Performances of Metal Oxide Nanostructures for Detecting Dissolved Gases: A Mini Review

Contact Info

Product

Resources

About