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Journal ArticleDOI

Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensor.

15 Jul 2016-Nanotechnology (IOP Publishing)-Vol. 27, Iss: 34, pp 345502-345502

TL;DR: The impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor is reported and the relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZNO using 1 kGy gamma ray treatment.

AbstractWe report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor's performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment.

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Citations
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Journal ArticleDOI
TL;DR: In this paper, several techniques related to the synthesis of ZnO nanostructures and their efficient performance in sensing are reviewed, such as functionalization of noble metal nanoparticles, doping of metals, inclusion of carbonaceous nanomaterials, using nanocomposites of different MO x, UV activation, and post-treatment method of high-energy irradiation on ZnOs, with their possible sensing mechanisms.
Abstract: Metal oxide semiconductors-based gas sensors have been extensively explored due to their high sensing response, cost-effectivity, long-term stability, and simple fabrication. However, their utilization at low operating temperature is still challenging. Thus, reduction in power consumption is highly essential for long-term usage of gas sensors. ZnO nanostructures-based gas sensors are one of the most eligible candidates where a real-time detection of explosive and toxic gases is needed. On this subject, numerous efforts have been made to improve the sensing response at reduced working temperature with the assistance of various methods. In this report, several techniques related to the synthesis of ZnO nanostructures and their efficient performance in sensing are reviewed. The report primarily focuses on different means of improving the sensing properties, such as functionalization of noble metal nanoparticles, doping of metals, inclusion of carbonaceous nanomaterials, using nanocomposites of different MO x , UV activation, and post-treatment method of high-energy irradiation on ZnO nanostructures, with their possible sensing mechanisms. This study will therefore shed light on future proposals of ZnO-based gas sensors showing high sensitivity even at low operating temperature.

135 citations

Journal ArticleDOI
TL;DR: In this article, the mesoporous In2O3 sensors exhibited good reversibility and repeatability towards hydrogen gas and showed a good selectivity for hydrogen compared to other commonly investigated gases including NH3, CO, ethyl alcohol, styrene, CH2Cl2 and formaldehyde.
Abstract: Hydrogen gas sensors were fabricated using mesoporous In2O3 synthesized using hydrothermal reaction and calcination processes. Their best performance for the hydrogen detection was found at a working temperature of 260 °C with a high response of 18.0 toward 500 ppm hydrogen, fast response/recovery times (e.g. 1.7 s/1.5 s for 500 ppm hydrogen), and a low detection limit down to 10 ppb. Using air as the carrier gas, the mesoporous In2O3 sensors exhibited good reversibility and repeatability towards hydrogen gas. They also showed a good selectivity for hydrogen compared to other commonly investigated gases including NH3, CO, ethyl alcohol, ethyl acetate, styrene, CH2Cl2 and formaldehyde. In addition, the sensors showed good long-term stability. The good sensing performance of these hydrogen sensors is attributed to the formation of mesoporous structures, large specific surface areas and numerous chemisorbed oxygen ions on the surfaces of the mesoporous In2O3.

51 citations

Journal ArticleDOI
TL;DR: In this paper, a vertically aligned single crystalline ZnO nanorods arrays were grown on a silicon substrate in a CVD reactor using Au as a catalyst, and the structural and morphological properties of the resulting nanorod arrays were studied by means of X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction and field emission scanning microscopy.
Abstract: Vertically aligned single crystalline ZnO nanorods arrays were grown on a silicon substrate in a CVD reactor using Au as a catalyst. The CVD parameters such as substrate temperature, catalyst layer thickness/morphology and reaction time play a crucial role in the synthesis of nanostructures by the vapor-liquid-solid process. By optimizing these various CVD parameters, highly controlled guided growth of ZnO nanorods was achieved. The structural and morphological properties of resultant ZnO nanorods were studied by means of X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction and field emission scanning electron microscopy. The photoluminescence spectroscopy was also done to investigate the defects in grown ZnO nanorods. The field emission results of nanorods array indicated that the properties of the field emission follow Fowler–Nordheim law. The nanorods (grown for 20 min) are vertically aligned on the substrate surface without entanglements and with good crystal quality as well which is very important for several applications.

19 citations

Journal ArticleDOI
TL;DR: A high selectivity of the proposed sensor with respect to ammonia, sulfur dioxide and organic vapours such as acetone, methanol, chlorobenzene, and chloroform has also been achieved due to nanostructure ZnO film.
Abstract: This paper reports an interdigitated metal-semiconductor-metal (MSM) based hydrogen gas (H2) sensor using colloidal zinc oxide (ZnO) quantum dots (QDs) as the sensing material. The active layer is obtained by spin coating of as-synthesized colloidal ZnO QDs on a SiO2/Si substrate in which the SiO2 layer is grown by oxidation of the Si substrate. The surface morphology of a ZnO QDs -based active film is measured using scanning electron microscopy (SEM) and atomic force microscopy (AFM) support for enhanced gas response. The change in current is measured for different concentrations of H2 gas at 175 °C in an ambient air atmosphere. Reasonably good gas responses of ∼41% for 1% H2 gas and 83.2% for 4% H2 gas have been obtained in ambient air condition. A high selectivity of the proposed sensor with respect to ammonia, sulfur dioxide and organic vapours such as acetone, methanol, chlorobenzene, and chloroform has also been achieved due to nanostructure ZnO films.

15 citations


References
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Journal ArticleDOI
TL;DR: In this paper, a review examines the potential benefits of these technologies across different markets, particularly the current state of development and performance of fuel cell micro-CHP, and the potential contribution of hydrogen and fuel cells to low-carbon energy systems.
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392 citations

Journal ArticleDOI
30 May 2012-Sensors
TL;DR: This article reviews and evaluates the performance of 1-D nanostructured metal-oxide gas sensors based on ZnO, SnO 2, TiO2, In2O3, WOx, AgVO3, CdO, MoO 3, CuO, TeO2 and Fe2O2.
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386 citations