scholarly journals Influence of Al Doping on the Morphological, Structural and Gas Sensing Properties of Electrochemically Deposited ZnO Films on Quartz Resonators

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 81
Author(s):  
Gergana Alexieva ◽  
Konstantin Lovchinov ◽  
Miroslav Petrov ◽  
Rositsa Gergova ◽  
Nikolay Tyutyundzhiev

The detection of hazardous gases at different concentration levels at low and room temperature is still an actual and challenging task. In this paper, Al-doped ZnO thin films are synthesized by the electrochemical deposition method on the gold electrodes of AT-cut quartz resonators, vibrating at 10 MHz. The average roughness, surface morphology and gas sensing properties are investigated. The average roughness of Al-doped ZnO layers strongly depends on the amount of the doping agent Al2(SO4)3 added to the solution. The structural dependence of these films with varying Al concentrations is evident from the scanning electron microscopy images. The sensing properties to ethanol and ammonia analytes were tested in the range of 0–12,800 ppm. In the analysis of the sensitivity to ammonia, a dependence on the concentration of the added Al2(SO4)3 in the electrochemically deposited layers is also observed, as the most sensitive layer is at 3 × 10−5 M. The sensitivity and the detection limit in case of ammonia are, respectively, 0.03 Hz/ppm and 100 ppm for the optimal doping concentration. The sensitivity depends on the active surface area of the layers, with those with a more developed surface being more sensitive. Al-doped ZnO layers showed a good long-term stability and reproducibility towards ammonia and ethanol gases. In the case of ethanol, the sensitivity is an order lower than that for ammonia, as those deposited with Al2(SO4)3 do not practically react to ethanol.

RSC Advances ◽  
2016 ◽  
Vol 6 (31) ◽  
pp. 26227-26238 ◽  
Author(s):  
David E. Motaung ◽  
Ioannis Kortidis ◽  
Gugu H. Mhlongo ◽  
Mart-Mari Duvenhage ◽  
Hendrik. C. Swart ◽  
...  

Schematic diagram showing the 2D TOF SIMS overlays of Si+, Mn+and Zn+. The insert corresponds to the correlation between the sensing response and FMR signal as a function of Mn concentration when exposed to various gases.


2014 ◽  
Vol 3 (2) ◽  
pp. 331-334 ◽  
Author(s):  
S. Kishimoto ◽  
S. Akamatsu ◽  
H. Song ◽  
J. Nomoto ◽  
H. Makino ◽  
...  

Abstract. The carbon monoxide (CO) gas sensing properties of low-resistance heavily Ga-doped ZnO thin films were evaluated. The ZnO films with a thickness of 50 nm were deposited at 200 °C by ion plating. The electrical properties of the ZnO films were controlled by varying the oxygen assist gas flow rate during deposition. The CO gas sensitivity of ZnO films with Au electrodes was investigated in nitrogen gas at a temperature of 230 to 330 °C. CO gas concentration was varied in the range of 0.6–2.4% in nitrogen gas. Upon exposure to CO gas, the current flowing through the film was found to decrease. This response occurred even at the lowest temperature of 230 °C, and is thought to be the result of a mechanism different than the previously reported chemical reaction.


2011 ◽  
Vol 519 (18) ◽  
pp. 6151-6154 ◽  
Author(s):  
Xiaoyan Zhou ◽  
Qingzhong Xue ◽  
Ming Ma ◽  
Jianpeng Li

2014 ◽  
Vol 2 (39) ◽  
pp. 16697-16706 ◽  
Author(s):  
Shouli Bai ◽  
Song Chen ◽  
Yangbo Zhao ◽  
Teng Guo ◽  
Ruixian Luo ◽  
...  

The response of ZnO nanofibers is significantly enhanced via Cd doping, which can be attributed to the change of defects in ZnO and has been confirmed by PL and XPS analysis.


2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540043 ◽  
Author(s):  
P. N. Shelke ◽  
Y. B. Khollam ◽  
S. D. Gunjal ◽  
P. M. Koinkar ◽  
S. R. Jadkar ◽  
...  

Present communication reports the LPG and NH 3 sensing properties of Co 3 O 4 films prepared on throughly cleaned stainless steel (SS) and copper ( CU ) substrates by using DC electrochemical deposition method followed by air annealing at 350°C/2 h. The resultant films are characterized by using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The LPG and NH 3 gas sensing properties of these films are measured at room temperature (RT) by using static gas sensing system at different concentrations of test gas ranging from ~ 25 ppm to 350 ppm. The XRD and Raman spectroscopy studies clearly indicated the formation of pure cubic spinel Co 3 O 4 in all films. The LPG and NH 3 gas sensing properties of films showed (i) the increase in sensitivity factor (S.F.) with gas concentrations and (ii) more sensibility to LPG as compared to NH 3 gas. In case of NH 3 gas (conc. ~ 150 ppm) and LPG gas (conc. ~ 60 ppm) sensing, the maximum S.F. = 270 and 258 are found for the films deposited on CU substrates, respectively. For all films, the response time (3–5 min.) is found to be much higher than the recovery time (30–50 sec). For all films, the response and recovery time are found to be higher for LPG as compared to NH 3 gas. Further, repeatability–reproducibility in gas sensing properties is clearly noted by analysis of data for number of cycles recorded for all films from different set of depositions.


2018 ◽  
Vol 212 ◽  
pp. 292-295 ◽  
Author(s):  
T. Çorlu ◽  
I. Karaduman ◽  
S. Galioglu ◽  
B. Akata ◽  
M.A. Yıldırım ◽  
...  

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