Vertically Aligned Mn-doped Fe3O4 Nanowire Arrays: Magnetic Properties and Gas Sensing at Room Temperature

2007 ◽  
Vol 1032 ◽  
Author(s):  
Seon Oh Hwang ◽  
Chang Hyun Kim ◽  
Yoon Myung ◽  
Seong-Hun Park ◽  
Jeunghee Park ◽  
...  

AbstractVertically-aligned Mn (10%)-doped Fe3O4 (Fe2.7Mn0.3O4) nanowire arrays were produced by the reduction/substitution of pre-grown Fe2O3 nanowires. These nanowires were ferromagnetic with a Verwey temperature of 129 K. X-ray magnetic circular dichroism measurements revealed that the Mn2+ ions preferentially occupy the tetrahedral sites, substituting for the Fe3+ ions. We observed that the Mn substitution decreases the magnetization, but increases the electrical conductivity. We developed highly sensitive gas sensors using these nanowire arrays, operating at room temperature, whose sensitivity showed a correlation with their bond strength of diatomic/triatomic molecules. Based on the fact that the sensitivity was highest toward water vapor, an excellent-performance humidity sensor was fabricated.

2008 ◽  
Vol 112 (36) ◽  
pp. 13911-13916 ◽  
Author(s):  
Seon Oh Hwang ◽  
Chang Hyun Kim ◽  
Yoon Myung ◽  
Seong-Hun Park ◽  
Jeunghee Park ◽  
...  

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3815
Author(s):  
Renyun Zhang ◽  
Magnus Hummelgård ◽  
Joel Ljunggren ◽  
Håkan Olin

Metal-semiconductor junctions and interfaces have been studied for many years due to their importance in applications such as semiconductor electronics and solar cells. However, semiconductor-metal networks are less studied because there is a lack of effective methods to fabricate such structures. Here, we report a novel Au–ZnO-based metal-semiconductor (M-S)n network in which ZnO nanowires were grown horizontally on gold particles and extended to reach the neighboring particles, forming an (M-S)n network. The (M-S)n network was further used as a gas sensor for sensing ethanol and acetone gases. The results show that the (M-S)n network is sensitive to ethanol (28.1 ppm) and acetone (22.3 ppm) gases and has the capacity to recognize the two gases based on differences in the saturation time. This study provides a method for producing a new type of metal-semiconductor network structure and demonstrates its application in gas sensing.


FlatChem ◽  
2018 ◽  
Vol 9 ◽  
pp. 21-26 ◽  
Author(s):  
S.G. Leonardi ◽  
W. Wlodarski ◽  
Y. Li ◽  
N. Donato ◽  
Z. Sofer ◽  
...  

2019 ◽  
Vol 288 ◽  
pp. 625-633 ◽  
Author(s):  
Hwan-Seok Jeong ◽  
Min-Jae Park ◽  
Soo-Hun Kwon ◽  
Hyo-Jun Joo ◽  
Hyuck-In Kwon

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6475
Author(s):  
Jiahui Guo ◽  
Weiwei Li ◽  
Xuanliang Zhao ◽  
Haowen Hu ◽  
Min Wang ◽  
...  

Semiconducting metal oxides can detect low concentrations of NO2 and other toxic gases, which have been widely investigated in the field of gas sensors. However, most studies on the gas sensing properties of these materials are carried out at high temperatures. In this work, Hollow SnO2 nanofibers were successfully synthesized by electrospinning and calcination, followed by surface modification using ZnO to improve the sensitivity of the SnO2 nanofibers sensor to NO2 gas. The gas sensing behavior of SnO2/ZnO sensors was then investigated at room temperature (~20 °C). The results showed that SnO2/ZnO nanocomposites exhibited high sensitivity and selectivity to 0.5 ppm of NO2 gas with a response value of 336%, which was much higher than that of pure SnO2 (13%). In addition to the increase in the specific surface area of SnO2/ZnO-3 compared with pure SnO2, it also had a positive impact on the detection sensitivity. This increase was attributed to the heterojunction effect and the selective NO2 physisorption sensing mechanism of SnO2/ZnO nanocomposites. In addition, patterned electrodes of silver paste were printed on different flexible substrates, such as paper, polyethylene terephthalate and polydimethylsiloxane using a facile screen-printing process. Silver electrodes were integrated with SnO2/ZnO into a flexible wearable sensor array, which could detect 0.1 ppm NO2 gas after 10,000 bending cycles. The findings of this study therefore open a general approach for the fabrication of flexible devices for gas detection applications.


RSC Advances ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 1157-1164
Author(s):  
Parag V. Adhyapak ◽  
Aishwarya M. Kasabe ◽  
Amruta D. Bang ◽  
Jalindar Ambekar ◽  
Sulabha K. Kulkarni

A novel, highly sensitive gold nanowire (AuNW) resistive sensor is reported here for humidity sensing in the relative humidity range of 11% to 92% RH as well as for breath sensing.


NANO ◽  
2018 ◽  
Vol 13 (09) ◽  
pp. 1850108 ◽  
Author(s):  
Z. Feng ◽  
K. Q. Lin ◽  
Y. C. Chen ◽  
S. L. Cheng

In this study, the controllable fabrication of a variety of vertically aligned, single-crystalline [110]-oriented Si nanowire arrays with sharp tips on (110)Si substrates is achieved using a combined self-assembled nanosphere lithography and multiple electroless Ag-catalyzed Si etching processes. All of the experiments were performed at room temperature. The morphological evolution and formation mechanism of long tapered [110]Si nanowire arrays during the multiple tip-sharpening cycle processes have been investigated by scanning electron microscopy, transmission electron microscopy and water contact angle measurements. Field emission measurements demonstrate that the field-emission behaviors of all nanowire samples produced in this study agree well with the Fowler–Nordheim theory, and the produced long tapered [110]Si nanowire array possesses superior electron emission characteristics, with a very low turn-on field of 1.4[Formula: see text]V/[Formula: see text]m and a high field enhancement factor of 3816. The simple and room temperature fabrication of the well-ordered long tapered [110]Si nanowire array and its excellent electron field emission performance suggest that it can serve as a good candidate for applications in high-performance Si-based vacuum electronic nanodevices.


2014 ◽  
Vol 5 ◽  
pp. 910-918 ◽  
Author(s):  
Prasantha R Mudimela ◽  
Mattia Scardamaglia ◽  
Oriol González-León ◽  
Nicolas Reckinger ◽  
Rony Snyders ◽  
...  

Vertically aligned carbon nanotubes of different lengths (150, 300, 500 µm) synthesized by thermal chemical vapor deposition and decorated with gold nanoparticles were investigated as gas sensitive materials for detecting nitrogen dioxide (NO2) at room temperature. Gold nanoparticles of about 6 nm in diameter were sputtered on the top surface of the carbon nanotube forests to enhance the sensitivity to the pollutant gas. We showed that the sensing response to nitrogen dioxide depends on the nanotube length. The optimum was found to be 300 µm for getting the higher response. When the background humidity level was changed from dry to 50% relative humidity, an increase in the response to NO2 was observed for all the sensors, regardless of the nanotube length.


2015 ◽  
Vol 3 (7) ◽  
pp. 3529-3535 ◽  
Author(s):  
Penglei Wang ◽  
Yongming Fu ◽  
Binwei Yu ◽  
Yayu Zhao ◽  
Lili Xing ◽  
...  

Room-temperature self-powered ethanol sensing has been realized from ZnO nanowire arrays by combining their piezoelectric, photoelectric and gas sensing characteristics.


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